Freescale Semiconductor MCF51QE128RM Configuration/Status Register 2 CSR2, CSR2 Reference Summary

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Chapter 18 Version 1 ColdFire Debug (CF1_DEBUG)

 

Table 18-7. XCSR Field Descriptions (continued)

 

 

 

 

 

 

 

 

 

 

Field

 

 

 

Description

 

 

 

 

 

 

 

 

 

 

 

 

2–1

Automatic PC synchronization control. Determines the periodic interval of PC address captures, if

 

APCSC

XCSR[APCENB] is set. When the selected interval is reached, a SYNC_PC command is sent to the ColdFire

 

CPU. For more information on the SYNC_PC operation, see the APCENB description.

 

 

The chosen frequency depends on CSR2[APCDIV16] as shown in the equation and table below:

 

 

 

 

 

2(APCSC + 1) × 1024

Eqn. 18-1

 

 

PC address capture period = ----------------------------------------------------------

 

 

 

 

16APCDIV16

 

 

 

XCSR

CSR2

XCSR

 

SYNC_PC Interval

 

 

 

 

[APCENB]

[APCDIV16]

[APCSC]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

0

00

 

2048 cycles

 

 

 

 

 

 

 

 

 

 

 

 

 

1

0

01

 

4096 cycles

 

 

 

 

 

 

 

 

 

 

 

 

 

1

0

10

 

8192 cycles

 

 

 

 

 

 

 

 

 

 

 

 

 

1

0

11

 

16384 cycles

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

00

 

128 cycles

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

01

 

256 cycles

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

10

 

512 cycles

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

11

 

1024 cycles

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

Automatic PC synchronization enable. Enables the periodic output of the PC which can be used for PST/DDATA

APCENB

trace synchronization.

 

 

 

 

 

 

 

As described in XCSR[APCSC], when the enabled periodic timer expires, a SYNC_PC command is sent to the

 

ColdFire CPU which generates a forced instruction fetch of the next instruction. The PST/DDATA module captures

 

the target address as defined by CSR[9] (two bytes if CSR[9] is cleared, three bytes if CSR[9] is set). This

 

produces a PST sequence of 0x5 (indicating a taken branch), followed by the PST marker indicating a 2- or 3-byte

 

address, and then the captured instruction address.

 

 

 

 

 

0 Automatic PC synchronization disabled

 

 

 

 

 

 

1 Automatic PC synchronization enabled

 

 

 

 

 

 

 

 

 

 

 

 

 

 

18.3.3Configuration/Status Register 2 (CSR2)

The 32-bit CSR2 is partitioned into two sections. The upper byte contains status and configuration bits always accessible to the BDM interface, even if debug mode is disabled. The lower 24 bits contain fields related to the configuration of the PST trace buffer (PSTB).

There are multiple ways to reference CSR2. They are summarized in Table 18-8.

Table 18-8. CSR2 Reference Summary

Method

Reference Details

 

 

READ_CSR2_BYTE

Reads CSR2[3124] from the BDM interface. Available in all modes.

 

 

WRITE_CSR2_BYTE

Writes CSR2[3124] from the BDM interface. Available in all modes.

 

 

READ_DREG

Reads CSR2[310] from the BDM interface. Classified as a non-intrusive BDM command.

 

 

 

MCF51QE128 MCU Series Reference Manual, Rev. 3

 

 

Freescale Semiconductor

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Freescale Semiconductor MCF51QE128RM manual Configuration/Status Register 2 CSR2, CSR2 Reference Summary, Xcsr CSR2