Motorola MPC533 Reference Manual page 820

PPM Registers
Bits Name
0:7 —
8:17 SHORT_CH[7:0]
Register Name
SHORT_CH_REG
TX_DATA[0:15]
Data transmitted
SHORT_CH_REG
TX_DATA[0:15]
Data transmitted
SHORT_CH_REG
18-20
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
Table 18-8. SHORT_CH_REG Bit Descriptions
Reserved
Each bit of this field will short a specified pair of channels. Where a pair of channels are
shorted, the data for the shorted channel will be transmitted twice.
SHORT_CH[x] = 0 = No short.
SHORT_CH[7] = 1 Short TX_DATA[1] to TX_DATA[0], re-transmit TX_DATA[1] in
TX_DATA[0] bit time.
SHORT_CH[6] = 1 Short TX_DATA[3] to TX_DATA[2], re-transmit TX_DATA[3] in
TX_DATA[2] bit time.
SHORT_CH[5] = 1 Short TX_DATA[5] to TX_DATA[4], re-transmit TX_DATA[5] in
TX_DATA[4] bit time.
SHORT_CH[4] = 1 Short TX_DATA[7] to TX_DATA[6], re-transmit TX_DATA[7] in
TX_DATA[6] bit time.
SHORT_CH[3] = 1 Short TX_DATA[9] to TX_DATA[8], re-transmit TX_DATA[9] in
TX_DATA[8] bit time.
SHORT_CH[2] = 1 Short TX_DATA[11] to TX_DATA[10], re-transmit TX_DATA[11] in
TX_DATA[10] bit time.
SHORT_CH[1] = 1 Short TX_DATA[13] to TX_DATA[12], re-transmit TX_DATA[13] in
TX_DATA[12] bit time.
SHORT_CH[0] = 1 Short TX_DATA[15] to TX_DATA[14], re-transmit TX_DATA[15] in
TX_DATA[14] bit time.
Refer to the examples below which illustrate the effects of enabling SHORT_CH[7:0] bits.
Table 18-9. Examples of the SHORT_CH Bits
Register
Contents
0x0000
0x1234
0x1234
0x00F0
0x1234
0x3034
0x00FF
MPC533 Reference Manual
Description
Example 1
SHORT_CH[7:0] = 0x00, therefore no shorts enabled
0b 0001 0010 0011 0100
Normal transmission.
Example 2
SHORT_CH[7:4] = 1, therefore TX_DATA[1, 3, 5, 7]
are enabled for re-transmission.
0b 0001 0010 0011 0100
Underlines show bits to be re-transmitted
0b 0011 0000 0011 0100
Example 3
SHORT_CH[7:0] = 1, therefore bits (TX_DATA[1, 3, 5,
7, 9, 11, 13, 15] are enabled for re-transmission.
Comments
MOTOROLA