MPC555 / MPC556
TPU ROM FUNCTIONS
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
D-3
The functions in the Bank 1 entry table are identical to the Bank 0 entry table functions
with three exceptions. Function 1, SPWM, has been replaced by RWTPIN. This is a
function that allows reads and writes to the TPU time bases and corresponding pin.
Function 5, PPWA, is now an identification function in
. The microcode ROM
revision number is provided by this function. Finally, Function 7, MCPWM, has been
removed and left open for future use.
The CPU selects which entry table to use by setting the ETBANK field in the
TPUMCR2 register. This register is write once after reset. Although one entry table is
specified at start-up, it is possible, in some cases, to use functions from both
tables without resetting the microcontroller. A customer may, for example, wish to use
the ID function from Bank 1 to verify the TPU microcode version but then use the MCP-
WM function from Bank 0. As a customer will typically only run the ID function during
system configuration, and not again after that, the Bank 1 entry table can be changed
to the Bank 0 entry table using the soft reset feature of the TPU3. The procedure
should be:
1. Set ETBANK field in TPUMCR2 to 0b01 to select the entry table in Bank 1
2. Run the ID function
3. Stop the TPU3 by setting the STOP bit in the TPUMCR to one.
4. Reset the TPU3 by setting the SOFTRST bit in the TPUMCR2 register
5. Wait at least nine clocks
6. Clear the SOFTRST bit in the TPUMCR2 register
The TPU3 stays in reset until the CPU clears the SOFTRST bit. After the SOFTRST
bit has been cleared the TPU3 will be reset and the entry table in Bank 0 will be se-
lected by default. To select the Bank 0 entry table, write 0b00 to the ETBANK field in
Table D-2 Bank 1 Functions
Function
Number
Function
Nickname
Function Name
0xF
PTA
Programmable Time Accumulator
0xE
QOM
Queued Output Match
0xD
TSM
Table Stepper Motor
0xC
FQM
Frequency Measurement
0xB
UART
Universal Asynchronous Receiver/Transmitter
0xA
NITC
New Input Capture/Input Transition Counter
9
COMM
Multiphase Motor Commutation
8
HALLD
Hall Effect Decode
7
Reserved
6
FQD
Fast Quadrature Decode
5
ID
Identification
4
OC
Output Compare
3
PWM
Pulse Width Modulation
2
DIO
Discrete Input/Output
1
RWTPIN
Read/Write Timers and Pin
0
SIOP
Serial Input/output Port
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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