Motorola IH5 User Manual
5-6
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Remote Start Via the PCI Bus
5
Opcode 0x03: Write/Read Memory
This command allows the host to Read or Write individual address
locations on the local address bus. Data sizes of 8, 16 and 32 bits are
supported. The specific operation and size are determined by the command
options field. Note: Verbose mode target command processing is not
available with this command; command register bit 9 is ignored.
locations on the local address bus. Data sizes of 8, 16 and 32 bits are
supported. The specific operation and size are determined by the command
options field. Note: Verbose mode target command processing is not
available with this command; command register bit 9 is ignored.
❏
The data to be written is specified in the data field. If the options
specifies 32 bit writes, then the upper half of VR1 sources the upper
16 bits of the data (i.e. the data field can only provide the lower 16
bits). On reads, the read data is 0 extended to 32 bits and is stored in
VR1. The lower 16 bits of VR1 are returned in the result field.
specifies 32 bit writes, then the upper half of VR1 sources the upper
16 bits of the data (i.e. the data field can only provide the lower 16
bits). On reads, the read data is 0 extended to 32 bits and is stored in
VR1. The lower 16 bits of VR1 are returned in the result field.
❏
The address to be used for the access is taken from VR0.
Command option bits affect the operation as follows:
❏
Bit 15 indicates read (0) or write (1) operation
❏
Bit 14 indicates whether to auto-increment VR0 after the access is
performed. If 0, the contents of VR0 is unaffected by this command.
If 1, the contents of VR0 is incremented by 1,2 or 4 depending on
the size of the access.
performed. If 0, the contents of VR0 is unaffected by this command.
If 1, the contents of VR0 is incremented by 1,2 or 4 depending on
the size of the access.
The autoincrement feature may be used during downloads of
sequential data to avoid the overhead of issuing an additional write
virtual register command after each datum is written.
sequential data to avoid the overhead of issuing an additional write
virtual register command after each datum is written.
❏
Bit 12 & 13 specify the size of the access. 00 indicates an 8 bit, 01
indicates a 16 bit and 10 indicates 32 bits
indicates a 16 bit and 10 indicates 32 bits
Opcode 0x04: Checksum Memory
This command calculates the 16 bit checksum (specified at the end of this
chapter in the section titled Reference Function: srom_crc.c) and returns
the result in the result field. This is useful for determining whether a
download image is intact without incurring the overhead of reading each
location in the image using the memory read command.
chapter in the section titled Reference Function: srom_crc.c) and returns
the result in the result field. This is useful for determining whether a
download image is intact without incurring the overhead of reading each
location in the image using the memory read command.