User manual

AN020201-0904 Summary
4
Application Note
Battery-Level Detection in Z8 GP MCU Peripherals
Voltage Detection and Flags
The Low Voltage Detection register (LVD, register 0Ch at the expanded register
bank 0Dh) offers an option to monitor V
CC
voltage. Voltage detection is enabled
when bit 0 of LVD register is set. After voltage detection is enabled, the V
CC
level
is monitored in real time. The HVD flag (bit 2 of the LVD register) Is set only if V
CC
is higher than V
HVD
. The LVD flag (bit 1 of the LVD register) is set only if V
CC
is
lower than the V
LVD
.
When voltage detection is enabled, the LVD flag also triggers an interrupt request
at bit 5. IRQ5 latches the low voltage condition until it is cleared by instructions or
is reset. The IRQ5 interrupt is served if it is enabled in the IMR register. Other-
wise, bit 5 of the IRQ register is latched as a flag only.
Voltage detection is automatically disabled in STOP mode.
Summary
ZiLOG’s family of Z8 GP MCUs provides a highly-integrated but low-cost solution
to infrared remote control and other general-purpose applications. It offers
advanced voltage detection to monitor battery voltage in different stages. It fea-
tures a maximum input/output pin and built-in Power-On Reset, Voltage Brown-
Out protection. Two comparators enable the user to detect different levels (even
zero) of crossing detection while running on alternate current.
The ZGP323 device offers a low-cost OTP solution to pilot runs or small volume
production. It cuts down the supply chain greatly from that of mask ROM produc-
tion. The user can program OTP memory at the last minute and save consider-
able time over typical ROM masking.
The user can employ ZiLOG’s standard easy-to-use support tools, complete with
a C compiler, a trace buffer, and event triggering. The Z8 GP Application Board
provides full peripherals with an EEPROM, a learning remote circuit, and test
points. ZiLOG’s development tools enable the user to complete design work in a
much shorter period.
If the user has already designed in with ZiLOG’s Z86L88 family of devices, the
application can be migrated to the Z8 GP family with minimum effort. ZiLOG’s Z8
GP MCUs are 100% firmware- and hardware-compatible with the Z86L88 family.
This Application Note provides some checkpoints for the design conversion and is
also useful as a general guide for incorporating the Z8 GP microcontroller into
your design.
As always, ZiLOG is happy to assist you in your design efforts. Please feel free to
contact the ZiLOG Technical Support Group.
Note:
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