Freescale Semiconductor MCF51QE128RM manual PSTBWA7, Pstb Valid Data Locations Oldest to Newest

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Chapter 18 Version 1 ColdFire Debug (CF1_DEBUG)

 

 

Table 18-9. CSR2 Field Descriptions (continued)

 

 

 

 

 

 

 

Field

 

 

 

 

Description

 

 

 

 

 

22–21

PST trace buffer state. Indicates the current state of the PST trace buffer recording.

PSTBST

00 PSTB disabled

 

 

 

01 PSTB enabled and waiting for the start condition

 

10 PSTB enabled, recording and waiting for the stop condition

 

11 PSTB enabled, completed recording after the stop condition was reached

 

 

 

 

 

 

20

Reserved, must be cleared.

 

 

 

 

 

 

 

19–16

Debug 1-pin hardware revision level. Indicates the hardware revision level of the 1-pin debug module implemented

D1HRL

in the ColdFire core. For this device, this field is 0x0.

 

 

 

 

 

15–8

PST trace buffer write address. Indicates the current write address of the PST trace buffer. The most-significant-bit

PSTBWA

of this field is sticky, that is, once set, it remains set until a PST/DDATA reset event occurs. As the ColdFire core

 

inserts PST and DDATA packets into the trace buffer, this field is incremented. The value of the write address

 

defines the next location in the PST trace buffer to be loaded. In other words, the contents of PSTB[PSTBWA-1]

 

is the last valid entry in the trace buffer.

 

 

 

The msb of this field can be used to determine if the entire PST trace buffer has been loaded with valid data.

 

 

 

 

 

 

 

 

 

 

PSTBWA[7]

 

PSTB Valid Data Locations

 

 

 

 

 

(Oldest to Newest)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

0, 1, ... PSTBWA-1

 

 

 

 

 

 

 

 

 

 

 

1

 

PSTBWA, PSTBWA+1,..., 0, 1, PSTBWA-1

 

 

 

 

 

 

 

The PSTBWA is unaffected when a buffer stop condition has been reached, the buffer is disabled, or a system

 

reset occurs. This allows the contents of the PST trace buffer to be retrieved after these events to assist in debug.

 

 

 

 

 

7

PST trace buffer reset. Generates a reset of the PST trace buffer logic, which clears PSTBWA and PSTBST. The

PSTBR

same resources are reset whenever a disabled trace buffer becomes enabled and upon the receipt of a BDM GO

 

command when operating in continuous trace mode. These reset events also clear any accumulation of PSTs.

 

This bit always reads as a zero.

 

 

 

0

Do not force a PST trace buffer reset

 

 

 

1

Force a PST trace buffer reset

 

 

 

 

 

 

 

6

Automatic PC synchronization divide cycle counts by 16. This bit divides the cycle counts for automatic SYNC_PC

APCDIV16

command insertion by 16. See the APCSC and APCENB field descriptions.

 

 

 

 

 

 

5

Reserved, must be cleared.

 

 

 

 

 

 

 

 

 

MCF51QE128 MCU Series Reference Manual, Rev. 3

Freescale Semiconductor

369

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Freescale Semiconductor MCF51QE128RM manual PSTBWA7, Pstb Valid Data Locations Oldest to Newest