Motorola MPC533 Reference Manual page 1020

RCPU Development Access
22.9.3 Throughput
The tool can send a DSDI data message into device upon the receipt of a DSDO data
message as soon as the tool decodes the first two status bits of the DSDO data message just
received and confirms valid data from the RCPU.
An example throughput analysis is performed with the following assumptions:
• READI configuration of RCPU development access and debug mode is already
entered through READI
• The module is configured for reduced port mode
• MCKI running at 28 MHz
• MCKO running at 40 MHz
• 40-MHz internal operation
• READI auxiliary input and output signals are free (not in middle of transmission)
• No delay from tool in responding — tool keeps up with READI port
• Tool reads the complete DSDO data message before shifting in DSDI data message
• 10 clocks estimated to format and encode/decode DSDI data and DSDO data
messages within READI
The DSDI data message is 41 bits (six bits of TCODE and 35 bits of DSDI data.). It takes
41 clocks (41 bits / 1 MDI signals) to shift in the DSDI data message. It is estimated that
READI will take approximately 10 clocks to decode the DSDI data message. After the
message has been decoded, READI will take 35 clocks to serially shift in the 35 bits of
DSDI data to the RCPU development port. Hence, it takes a total of 86 clocks (41 + 10 +
35) to decode and shift in DSDI data from the tool to the RCPU development port.
At 28 MHz, it translates to 3079 ns (35.8 x 81) to decode and shift in DSDI data to RCPU
development port
As DSDI bits are shifted into the RCPU development register, DSDO bits are shifted out
from the same RCPU development register (DPDR) and these are captured by READI.
It is estimated that READI will take approximately 10 clocks to encode the DSDO data.
The DSDO message is 41 bits (6 bits of TCODE and 35 bits of DSDO data). It will take 21
clocks (41 bits / 2 MDO signals) for READI to transmit this message. Hence, it will take a
total of 31 clocks (10 + 21) to encode the DSDO data message and shift out the DSDO data
message to the tool.
22.9.4 Development Access Timing Diagrams
Figure 22-83 shows the timing diagram of RCPU development access and entering debug
mode out-of-system reset through READI.
22-88
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
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