Freescale Semiconductor MC9S12ZVM series, Справочное руководство

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Chapter 5 Background Debug Controller (S12ZBDCV2)
MC9S12ZVM Family Reference Manual Rev. 1.3
172 Freescale Semiconductor
5.4.5.2.2 READ_SAME Effects Of Variable Access Size
READ_SAME uses the unadjusted address given in the previous READ_MEM command as a base
address for subsequent READ_SAME commands. When the READ_MEM and READ_SAME size
parameters differ then READ_SAME uses the original base address buts aligns 32-bit and 16-bit accesses,
where those accesses would otherwise cross the aligned 4-byte boundary.
Table 5-12 shows some
examples of this.
d
5.4.6 BDC Serial Interface
The BDC communicates with external devices serially via the BKGD pin. During reset, this pin is a mode
select input which selects between normal and special modes of operation. After reset, this pin becomes
the dedicated serial interface pin for the BDC.
The BDC serial interface uses an internal clock source, selected by the CLKSW bit in the BDCCSR
register. This clock is referred to as the target clock in the following explanation.
Table 5-12. Consecutive READ_SAME Accesses With Variable Size
Row Command Base Address 00 01 10 11
1 READ_MEM.32 0x004003 Accessed Accessed Accessed Accessed
2 READ_SAME.32 — Accessed Accessed Accessed Accessed
3 READ_SAME.16 — Accessed Accessed
4 READ_SAME.08 — Accessed
5 READ_MEM.08 0x004000 Accessed
6 READ_SAME.08 — Accessed
7 READ_SAME.16 — Accessed Accessed
8 READ_SAME.32 — Accessed Accessed Accessed Accessed
9 READ_MEM.08 0x004002 Accessed
10 READ_SAME.08 — Accessed
11 READ_SAME.16 — Accessed Accessed
12 READ_SAME.32 — Accessed Accessed Accessed Accessed
13 READ_MEM.08 0x004003 Accessed
14 READ_SAME.08 — Accessed
15 READ_SAME.16 — Accessed Accessed
16 READ_SAME.32 — Accessed Accessed Accessed Accessed
17 READ_MEM.16 0x004001 Accessed Accessed
18 READ_SAME.08 — Accessed
19 READ_SAME.16 — Accessed Accessed
20 READ_SAME.32 — Accessed Accessed Accessed Accessed
21 READ_MEM.16 0x004003 Accessed Accessed
22 READ_SAME.08 — Accessed
23 READ_SAME.16 — Accessed Accessed
24 READ_SAME.32 — Accessed Accessed Accessed Accessed