DESCRIPTION OF PIN FUNCTIONS
PIN NO.
46
NAME
Terminal Count
TC
SYMBOL
BUFFER
TYPE
O8
DESCRIPTION
This active high output is asserted with
the last DMA data transfer to indicate to
the System that the DMA data transfer is
complete. TC is asserted in conjunction
with DACK.
The remote system indicates that it is
ready to perform DMA transfers by
driving this line high. This signal is
asserted as long as the System is ready
to receive or send data and is deasserted
on the last byte of the data transfer.
Pulling this line low enables the
watchdog. The watchdog will generate
four beeps on the piezo driver if there are
no transitions on the host port lines for a
minute.
This
circuitry
can
also
automatically power down the system
when the watchdog "barks". This feature
requires software to tickle the port every
30 seconds.
Pulling this line low for two SYSCLKs will
reset the PPC34C60 to its initial state.
This will reset all internal registers to their
default values.
A low level on this input line signals that
the battery power is low and the
PPC34C60 will generate low battery
tones. It is the responsibility of the
remote system to monitor battery power
and generate this input signal.
The host may obtain the level at these
pins by reading the Internal Input
Register.
This high current output can be directly
hooked up to a piezo speaker to provide
audio tones.
These pins are individually configured as
general purpose outputs or as strobe
outputs as programmed in the Output
Configuration Register. ST2 may also be
programmed as the Auto-Power pin.
These pins are individually configured as
general purpose outputs or as chip select
outputs as programmed in the Output
Configuration Register.
A parallel resonant crystal or RC network
may be placed across YIN and YOUT.
This nominal 32KHz clock (32.768KHz) is
used by the internal piezo driver and
watchdog timer.
47
DMA Request
DREQ
I, PD
MISCELLANEOUS
39
nWatchdog Enable
nWDOGEN
I, PU
34
nReset Chip
nRESET
I, PU
35
nLow
Indicator
Battery nLBAT
I, PU
82,83,
37,36
38
General Purpose IN[0:3]
Inputs [0:3]
Piezo Crystal Drive
PIEZO
I, PU
O24
44,43, 42 nStrobes[0:2]
(special function)
nST[0:2]
O8
84-87
nChip Selects[0:3] nCS[0:3]
(special function)
O8
32
31
Oscillator Input
Oscillator Output
YIN
YOUT
I
08
SMSC DS – PPC34C60
Page 9
Rev. 06/01/2001
ADVANCED INFORMATION
SMSC [ SMSC CORPORATION ]
