Filter
Top Products
Debug Module
MCF52211 ColdFire® Integrated Microcontroller Reference Manual, Rev. 2
28-24 Freescale Semiconductor
28.5.3.1 ColdFire BDM Command Format
All ColdFire family BDM commands include a 16-bit operation word followed by an optional set of one
or more extension words.
28.5.3.1.1 Extension Words as Required
Some commands require extension words for addresses and/or immediate data. Addresses require two
extension words because only absolute long addressing is permitted. Longword accesses are forcibly
longword-aligned and word accesses are forcibly word-aligned. Immediate data can be 1 or 2 words long.
Byte and word data each requires a single extension word, while longword data requires two extension
words.
Operands and addresses are transferred most-significant word first. In the following descriptions of the
BDM command set, the optional set of extension words is defined as address, data, or operand data.
1514131211109876543210
Operation 0 R/W Op Size 0 0 A/D Register
Extension Word(s)
Figure 28-16. BDM Command Format
Table 28-21. BDM Field Descriptions
Field Description
15–10
Operation
Specifies the command. These values are listed in Table 28-20.
9 Reserved, must be cleared.
8
R/W
Direction of operand transfer.
0 Data is written to the CPU or to memory from the development system.
1 The transfer is from the CPU to the development system.
7–6
Op Size
Operand Data Size for Sized Operations. Addresses are expressed as 32-bit absolute values. A command
performing a byte-sized memory read leaves the upper 8 bits of the response data undefined. Referenced data is
returned in the lower 8 bits of the response.
5–4 Reserved, must be cleared.
3
A/D
Address/Data. Determines whether the register field specifies a data or address register.
0 Data register.
1 Address register.
2–0
Register
Contains the register number in commands that operate on processor registers. See Table 28-22.
Operand Size Bit Values
00 Byte 8 bits
01 Word 16 bits
10 Longword 32 bits
11 Reserved —