mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 1268

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

Memory Map and Register Descriptions
50.3.4 Configuration/Status Register 3 (CSR3)
The CSR3 contains fields enabling indirect writes to the DBGCR. Writes to these CSR3
fields execute 4-bit nibble writes to the DBGCR. Thus, writing to the entire 32-bit
DBGCR would require eight "write CSR3" commands be processed via the single-pin
BDM interface.
When read, CSR3 enables indirect reads of the DBGSR. When a "read CSR3" command
is transmitted on the single-pin BDM interface, one byte of DBGSR is read and returned.
The debug logic maintains a 2-bit counter that selects the byte of the DBGSR register to
be read, starting with DBGSR[7:0]. The 2-bit counter is cleared by POR and by any write
to the CSR3. It is incremented by any read of the CSR3. Thus, a read of the entire 32-bit
DBGSR would require four "read CSR3" commands be processed on the single-pin BDM
interface, and the sequential commands would return data in the following order:
DBGSR[7:0], DBGSR[15:8], DBGSR[23:16], and DBGSR[31:24].
This table summarizes the methods for accessing CSR3.
1268
READ_CSR3_BYTE
WRITE_CSR3_BYTE
READ_DREG
WRITE_DREG
WDEBUG instruction
DRc: 0x03 (CSR3)
R
W
Reset
R
W
Reset
31
0
15
0
0
UI
30
0
14
0
0
Method
29
0
13
0
0
NS
MCF51JF128 Reference Manual, Rev. 2, 03/2011
Table 50-14. CSR3 Reference Summary
28
0
12
0
0
27
0
11
0
0
26
0
10
0
0
WD
Preliminary
25
0
9
0
0
24
0
8
0
0
Reads bits CSR3[31–24] from the BDM interface. Available in
all modes.
Writes bits CSR3[31–24] from the BDM interface. Available in
all modes.
Reads bits CSR3[31–0] from the BDM interface. Classified as
a non-intrusive BDM command.
Writes bits CSR3[23–0] from the BDM interface. Classified as
a non-intrusive BDM command.
No operation while the core executes a WDEBUG instruction.
23
0
0
7
0
0
22
0
0
6
0
0
21
0
0
5
0
0
Reference Details
20
0
0
4
0
0
Freescale Semiconductor, Inc.
Access: Supervisor write-only
19
0
0
3
0
0
18
0
0
2
0
0
BDM read/write
17
0
0
1
0
0
16
0
0
0
0
0