Specifications
Freescale MC1321x Chip
This section applies to you if you are running SNAP on a “raw” MC1321x chip.
If you are running SNAP on a Panasonic PAN4555 or PAN4561 module which is based on the
MC1321x, please refer instead to one of the following sections.
The MC1321x port of SNAP implements 33 “IO” pins. (Refer to the SNAP 2.2 Migration Guide if
you do not understand the difference between an “IO” and a “GPIO.”)
The mapping is as follows:
PTA0-PTA7 are mapped to IO 0-7. These pins also support “wakeup” capability.
PTB0-PTB7 are mapped to IO 8-15. These pins can also be used as analog inputs.
PTC0-PTC7 are mapped to IO 16-23. PTC0/IO 16 can be used as the UART 1 TX. PTC1/IO 17 can be
used as the UART 1 RX. PTC4 is used as the PA_EN (Power Amplifier Enable) signal when enabled
by the corresponding Feature Bit (look at NV Configuration Parameter 11).
PTD2 is mapped to IO 24. This pin can also be used for full PWM.
PTD4-PTD7 are mapped to IO 25-28. These four pins can do PWM too, but can only vary the duty
cycle – the pulse frequency rate is fixed to 1 millisecond, because by default the underlying hardware
timer is providing the “1 millisecond time base” to the rest of the SNAP firmware. Setting feature bit
0x40 in NV Parameter 11 causes the system to use a different internal clock, allowing these four pins
to take full advantage of PWM.
PTE0-PTE1 are mapped to IO 29-30. PTE0/IO29 can also be used as the UART 0 TX. PTE1/IO 30
can be used as the UART 0 RX.
PTG1-PTG2 are mapped to IO 31-32.
The “missing” pins PTD0, PTD1, PTD3, and PTE2-PTE7 are used inside the MC1321x chip to
interface to the built-in radio. Since they could never be used for external hardware, we did not give
them “IO” numbers.
Some other hardware mappings:
PTA4/IO 4 can be the CTS output for UART 0.
PTA5/IO 5 can be the RTS input for UART 0.
PTA6/IO 6 can be the CTS output for UART 1.
PTA7/IO 7 can be the RTS input for UART 1.
The emulated I
2
C signals are on pins PTB0/IO 8 (SCK) and PTB1/IO 9 (SDA).
The emulated SPI signals are on pins PTG2/IO 32 (SCLK), PTG1/IO 31(MOSI), and PTD6/IO 27
(MISO).
SNAP Reference Manual Document Number 600-0007K Page 127 of 202