Z8/Z8Plus Microcontrollers -> Z8 FAQ
Q. What is the equation to calculate the ball park estimate for the RC Oscillator?
A. Please see attached to get RC Oscillator equation.
Q. What is the circuit to run 32KHz on the Z86C02/E02 using RC Oscillator?
A. Use 1meg ohm feedback resistor across the 32khz crystal. Then from each end of the crystal put 22pf going to ground on Xtal1 side and 100pf on Xtal2 side. Xtal1 input pin goes directly to the crystal. Xtal2 output pin is connected to a 56kohm resistor on one side. The other side of the 56kohm resistor is connected to the crystal. Please note that the 1megohm feedback resistor is in parallel with the crystal directly. Thus Rfb=1mohms and Rd=56kohms and c1=22pf and c2=100pf. The Z86E02/C02 must select the RC oscillator and Low EMI mode. See attached.
Q. What is the typical Icc current using Low EMI RC Oscillator circuit to run 32KHz on the Z86C02 3V to 5V range?
A. Use attached schematic to get typical values in ICC chart.
Q. What is the differences between the Z86E04 and Z86C04?
A. 1. The typical Tpor on the E04 is 50MS at 5V 25C while the C04 is about 9MS.
2. In Low EMI mode, the E04 output drive is reduced to 25% of Standard mode drive while to C04 remains in Standard mode drive.
3. The C04 has a ROM Mask Option to drive the WDT with the Xtal2 pin as a clock source while the E04 does not. Please note that when the Xtal2 is the WDT source, even though the permanent WDT is selected the WDT will not run in Stop mode. The reason is that the Xtal pins are turned off in Stop mode.
Q. My software for Z86E02 runs perfectly in CCP emulator but it fails in the target board?
A. CCP emulator contains every resource from E02 to 743. Problems would happen if the software tries to access resources that don't appear in the OTP itself. For Z86E02, quick checklist for such issue includes:
1. Make sure spl <= %40
2. Timer 0 must not be accessed.
3. Make sure program size < 512 bytes
4. Make sure ram size < %3f
5. Make sure the code (see below) for selecting stop mode using the emulator has been removed.
ld rp, #%0f
ld %0b, #00010100b
Q. Which revision is the correct revision for the Z86E02?
A. The most current revision is Z86E0208XXC1925
Q. Does the Z86E02 have an RC oscillator version?
A. The most current revision Z86E0208XXC1925 has the RC oscillator as an OTP option.
Q. Can the Z86E02 use a 32khz crystal?
A. The Z86E02 can run with a 32khz crystal in either RC oscillator mode or in crystal oscillator mode.
Q. How can I check on bench if the RC oscillator is enabled?
A. The easiest way to ensure that the RC oscillator is enabled is by seeing if the oscillator input has hysterisis or not. A crystal oscillator has no hysterisis between a high and a low while a RC oscillator has a Schmidt trigger input with hysterisis of at least 500mv.
Q. Can any Z8 OTP draw less current if the frequency was reduce to 10khz-32Khz range?
A. The Z8 OTP’s has a band gap structure in the EPROM that draws DC current of 700ua at Vcc of 5.0V and half that at 3.0V. The ROM versions does not have this band gap so they do not have this current limitation.
Q. What is the difference between the Z86E43 vs the Z86E40?
A.
2.The Z86E43 has a shorter
timeout on WDT than Z86E40. TWDT min is 3.5ms,7ms,14ms,
and 56ms at 5.0v on E43 while it is 5ms, 10ms, 20ms,and
80ms on the E40. 3.The Z86E43 reguires
a special adapter that plugs into the 18 pin programming
socket while the Z86E40 uses the 40pin programming socket
on the emulator. 4.The E40 typically has
the low voltage protection trip point of 2.6v
at 25c in run, halt, and stop modes. But the E43 has the low
voltage protection trip point of 2.8v at 25c in run and halt modes
while the low voltage protection trip point is 2.0v at 25c in
stop mode. Q. What is the difference
between the Z86E33 vs the Z86E30?
A.
2.The Z86E33 has a shorter
timeout on WDT than Z86E30. TWDT min is 3.5ms,7ms,14ms,
and 56ms at 5.0v on E33 while it is 5ms, 10ms, 20ms,
and 80ms on the E30. 3.The Z86E33 reguires
a special adapter that plugs into the 18 pin programming
socket while the Z86E30 uses the 40pin programming socket
on the emulator. 4.The E30 typically has
the low voltage protection trip point of 2.6v
at 25c in run, halt, and stop modes. But the E33 has the low voltage
protection trip point of 2.8v at 25c in run and halt modes
while the low voltage protection trip point is 2.0v at 25c in
stop mode. Q. What 18pin Z8
can run 32khz with low icc run current?
A.
2.The same applies with
the low voltage versions of these Z8’s. 3.The inputs must be
at one of the power rails or it will draw current. 4.Due to the gap band
in the EPROM, the Z8 OTP can not come close to this
low Icc at all. It is in the 300ua range. Q. What is recommended
to get the lowest Icc current for the Z8 ROM devices? A. 1.The Z8 ROM device’s
icc will drop as the frequency decreases. Q. What is difference
internally between a crystal oscillator circuit vs
a RC oscillator circuit? 1.The Z8 crystal oscillator
is essentially an inverter with 5MOhms feedback resistance
internally between Xtal1 and Xtal2 pins. The input of the inverter
has a single trip point to detect either a high or a low input
state. There is no hysterisis to speak of.The trip point
is normally set close to Vcc/2. 2.The Z8 RC oscillator circuit
is essentially an inverter with no feedback resistance internally
between Xtal1 and Xtal2. The input has a schmidt trigger input
with hysterisis of 500mV or more. The rule of thumb for where
the high trip point is Vcc/2 and the low trip point is one
diode drop below the hight trip point. Q. Does the Z8E000/001
and Z8PE002/003 support RC oscillator? A. Only the Z8PE002/003
presently support the RC oscillator. Q. Does the Z8E000/001
and Z8PE002/003 support WDT running in stop mode? A. None of these existing
Z8+ devices support WDT running in stop mode. Q. How much current
does the Z8E000/001 and Z8PE002/003 draw in run
mode? A. The WDT does not draw
any additional current in run mode. Q. Does the Z8E000/001
and Z8PE002/003 support 32KHz crystal oscillator? A. Only the Z8OE002/003
support 32khz crystal oscillator. Q. What is there
a difference in Tpor between the standard CMOS Z86X02/4/8
devices and OTP devices? A.
2.The Z86C08 and Z86E08
have the same Tpor but at 50ms at 5V 25C. 3. It is the Z86E04 and
Z86C04 that has different Tpor. The Z86C04 has typical of 6ms Tpor at 5V 25C
while the Z86E08 has typical of 50ms. 4.In future revisions
of the Z86X08, we will reduce the Tpor to match that of the Z86X04. Q. The CCP emulator
cannot emulate E02/E04/E08 rising edge interrupt source p32 (irq3). A. It was due to the difference
of hardware architecture from CCP and
Z8. A hardware modification to CCP emulator can help to fix.
There was one free invertor gate in u27 (74ls04) which could
be used. Connect pin 12 (p32) of 28 pin socket p2 to input
of the gate. The inverted output was connected to pin 18
(p30)of socket p2 then. The connection must be removed if Z86e3x/e4x
was being emulated instead. Q.
How to configure the Z86e40 to access 64k ROM and 64k ram? A. Access of program space
and data space was differentiated by the
/dm. It was set up by p3m register. ROMless pin must be active
if full addressing space was addressed, else only 60k
ROM and 60k ram could be accessed. Q.
OTP could not operate when ROM protect was selected but without
it. A. Select EPROM disable
instead of ROM protect upon OTP programming.
Z86E02/04/08 doesn't support lde and ldei upon
ROM protect. The OTP might not work if the software contained
these instructions. An effect of EPROM protect
worked like ROM protect. Q.
The OTP failed during operation. A. For a noisy environment:
2. Use permanent watch
dog timer and install WDT in the
software 3. Make sure the VCC
did not dropped below 3.5v throughout operation. 4. Connect xtal GND and
MCU GND together without sharing with other components. MCU VCC and GND should
be connected to power supply directly with thick and short traces with a single
contact to other components at the power supply only. Q. Can Z8 run below
3v? A. L-series - ok. Normal
operating voltage was from 2.0v to 3.9v. Z87l33
has a better range of 2.0v to 4.5v. C-series
- Z8 guaranteed to work if VCC > vlv if internal clock
sclk < 2mhz. Typical vlv was around 2.6v. E-series
- no. The minimum operation voltage was 3.5v for most of
the common devices, e.g. E02/04/08/3x/4x. Some special
devices might provide better or worse performance. Q.
Any items needed to be paid attention when programming with
adaptors, e.g. Dip-to-soic, e3x/4x adaptor? A.
2. Sometimes adding a
20pf to fast swiching data pin can help
the reliability of programming, e.g. The adclk pin. 3. Using adaptors for
other universal programmers in ZiLOG programming
equipments might require some modifications anyway, ZiLOG adaptors were recommended. Q. Common software
mistakes and important items? A.
2. All peripherals should
be defined under the limitations by
the databook. 3. Sph and Spl were clear
upon POR. 4. P34-p37 was set to
high upon POR. Q. Any methods to
have output disable and push-pull existed in the same
port, e.g p2? A. Select push pull for
port 2. For a particular bit to be Output
disabled, configure this bit as input instead. Q. Does ZiLOG Z86C40
series microcontroller have the same control
register file as the Z86C21 series? A. No. The Z86C40 has a
more powerful Stop mode, WDT mode, and port control
therefore it has extra control registers. Q.
Does zilog CCP emulator support all Z8 microcontrollers? A. No, the CCP supports
most of them, but not all of them. It supports Devices
in Z86X30/40, Z86X33/43, Z86X02/4/8, and Z86X03/06 families.
Q. What is the current
version of the boot ROM on the CCP? A. V 3.00 (at least on the
00zem version of the CCP). Q.
Does zilog have a pin for pin replacement for the pic16c54? A. Yes. The 86C02. There
is an application note in the app note data
book as well as on our web site. Q.
Can customers buy windowed OTP's? A. These are offered for
development purposes only (except for unusual
cases) Q. What do we (customers)
use to program OTP's? A. Usually the supporting
emulator not only emulates but programs OTP's.
Q.
Are external pull-ups required on I/O's? A. We have an auto latch
option on some Z8's while others have
internal programmable pull-ups. Q.
Does Zilog have parts with hardware PWM's? A. Yes, the Z8E001 has one
16bit t/c and one 16bit hw PWM. Q.
Does the code for say a .5k ROM part work for larger ROM? A. Yes! Unlike our competitors,
who must rewrite on migration, ZiLOG
code is 100% upwardly compatible (of course as long as they
contain the same set of peripherals, but the basic code for
control registers is in exactly the same place). Q.
Where does the code start execution after a reset? A. The code always start
at location 000c(hex). Q.
How does the Z8 deal with drooping supply voltages? A. Our brown out protection
guarantees the part will either be
in the active state or held in reset until the VCC once
again raises to operating range.. Q.
Does the on-chip oscillator of the Z86E02 work with an rc network? A. Yes, however, when ordering
the part order the Z86E02 SL1925. It is a OTP option. Q. Why is it that
new products are sampled prior to the release of an emulator
to support development and programming of that part? A. Zilog samples the parts
early and then works with its large volume
customers in beta trials of the emulator to ensure that when
the emulator, to support the new product, is released to the
general consumer/developer all of the bugs have been eliminated.
Q. I'm trying to use CCP emulator with my target board, but the I/O's aren't doing what they should be in 18 pin emulation.
A. The emulator is shipped with jumpers set to support a Z86E03/E06. These need to be changed to support the device that the caller is using.
Q. I'm getting a high fallout programming devices on my CCP.
A. They should be using the latest version of the GUI s/w. And usually, they haven't done the required modification to support the newer programming algorithms (remove capacitor c4 and add 2 - 0.1uf caps directly on the bottom side of the programming zif socket from VCC to GND and from VPP to GND.
Q. My application does not run anymore with the new Z86E02
A. If the customer has a SL1925 topmark, check the following:
1. Stack pointer (spl) must not be init to higher than 40h
2. Verify that user does not exceed specified ram range of 0-3fh this includes pointers and ram checksums.
3. Verify that user does not exceed specified ROM range of 0-1ffh this includes pointers to tables and ROM checksums.
Q. The oscillator on my Z86E02/04/08 design does not work reliably. I use a 8mhz crystal in standard osc/2 mode and have connected two caps of 27pf to GND. If i remove the cap at xtal1 it becomes better.
A. Besides some other reasons (see app note on-chip oscillator design and app. Note sw design techniques, appendix hw considerations, both printed in Z8 applications handbook), a simple reason may be this:
Verify if the customer has (unintentionally) received a SL1903 version of the Z86E02/04/08. These are dedicated rc main-oscillator devices and do not run with a crystal or ceramic resonator. In case of Z86E04/08, customer should use SL1866 versions. In case of Z86E02, customer should use our new SL1925 version, which has a programming option for rc-osc and crystal/resonator-osc.
Q. At what VCC is the ram content lost on OTPs, ROMs, ls?
A. We don't know exactly but its anywhere between 1.5 and 0.5v.
Q. My emulator works right but the OTP doesn't, why?
A. Check for the following:
1. Stack pointer is really on the highest ram location + 1. In most cases it's on the highest ram location + x.
2. Does the program only use the hardware which is on the OTP silicon? In most cases they use everything which is on the Z86C50.
3. Does sw use shadow registers for the ports? It's advisable to do.
4. Does sw mask port inputs? It's advisable to do.
5. Are the VPP, epm, /oe, /ce pins save? I.e. diodes to VCC EPROM/test mode disable
6. Does osc. Design meet the design rules?
7. Are there spices on VCC?
8. WDT driven from internal rc? WDT refreshed every 10msec.?
Q. One of the ports on the CCP doesn't work anymore.
A. This port was shot by overvoltage.
Q. Why is my yield low when i program OTPs?
A. Use latest programmer sw revision and enable the correct SL number
Q. My CCP will not program the OTPs that i have.
A. Check list:
- correct GUI version
- correct boot ROM (3.0)
- capacitor c4 has been taken off as per readme
- top mark selected correctly
- blank check?
- voltage correct for part (changed by pot)
Q. Z8 software runs on CCP but not on OTP
A . Check list:
- was CCP configured to part (maybe ROM/ram)?
- stack pointer set correctly?
- p01m bit set for internal/ external stack?
Q. Watchdog keeps cutting in when not used
A. On some parts, the watchdog reg does not need to be initialized for it to run if a watchdog refresh command exists. The timer can start on a refresh and will used default configuration.
Q. Timers run at the wrong speed
A. Check list:
- LOW EMI set correctly (alters internal clock)
- hardware divide taken into account
- prescalers set correctly (may not be direct value-value)
Q. How do I copy an extended reg on the Z8 to a normal register?
A. If rp is set for extended, local 4 bit addressing will access extended regs and 8 bit addressing will access normal regs (apart from working bank 00). Therefore, ld xxh, rx
Q. What happens to the Z8 ram during reset?
A. As long as the lower voltage boundary is maintained,ram is retained apart from spl and sph which are cleared during the reset.
Q. When I use single-step in CCP, the program accidentally resets. Why?
A. Single-step has exceeded 256
Q. The Z86x02 does not run at all. Just sits at the first command.
A. Is the working register group = 0 and the register = 0, ? If so, change ™ to a register greater than 3 in working register group zero (0). Register 0 to ™ register 3 are ports.
Q. What is the pin out for the SSOP package for Z86x02/04/08?
A. See attached.