Nxp Semiconductors UM10237 用户手册
UM10237_2
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 02 — 19 December 2008
703 of 792
NXP Semiconductors
UM10237
Chapter 31: LPC24XX On-chip bootloader for flashless parts
continue further transmission. If the check-sum does not match, the ISP command
handler responds with "RESEND<CR><LF>". In response the host should retransmit the
bytes.
handler responds with "RESEND<CR><LF>". In response the host should retransmit the
bytes.
6.5 Read Memory <address> <no. of bytes>
The data stream is followed by the command success return code. The check-sum is sent
after transmitting 20 UU-encoded lines. The checksum is generated by adding raw data
(before UU-encoding) bytes and is reset after transmitting 20 UU-encoded lines. The
length of any UU-encoded line should not exceed 61 characters(bytes) i.e. it can hold
45 data bytes. When the data fits in less then 20 UU-encoded lines then the check-sum is
of actual number of bytes sent. The host should compare it with the checksum of the
received bytes. If the check-sum matches then the host should respond with
"OK<CR><LF>" to continue further transmission. If the check-sum does not match then
the host should respond with "RESEND<CR><LF>". In response the ISP command
handler sends the data again.
after transmitting 20 UU-encoded lines. The checksum is generated by adding raw data
(before UU-encoding) bytes and is reset after transmitting 20 UU-encoded lines. The
length of any UU-encoded line should not exceed 61 characters(bytes) i.e. it can hold
45 data bytes. When the data fits in less then 20 UU-encoded lines then the check-sum is
of actual number of bytes sent. The host should compare it with the checksum of the
received bytes. If the check-sum matches then the host should respond with
"OK<CR><LF>" to continue further transmission. If the check-sum does not match then
the host should respond with "RESEND<CR><LF>". In response the ISP command
handler sends the data again.
Table 636. ISP Write to RAM command
Command
W
Input
Start Address:
RAM address where data bytes are to be written. This address
should be a word boundary.
Number of Bytes:
Number of bytes to be written. Count should be a multiple of 4
Return Code
CMD_SUCCESS |
ADDR_ERROR (Address not on word boundary) |
ADDR_NOT_MAPPED |
COUNT_ERROR (Byte count is not multiple of 4) |
PARAM_ERROR |
CODE_READ_PROTECTION_ENABLED
Description
This command is used to download data to RAM. Data should be in UU-encoded
format. This command is blocked when code read protection is enabled.
format. This command is blocked when code read protection is enabled.
Example
"W 1073742336 4<CR><LF>" writes 4 bytes of data to address 0x4000 0200.
Table 637. ISP Read Memory command
Command
R
Input
Start Address:
Address from where data bytes are to be read. This address
should be a word boundary.
Number of Bytes:
Number of bytes to be read. Count should be a multiple of 4.
Return Code
CMD_SUCCESS followed by <actual data (UU-encoded)> |
ADDR_ERROR (Address not on word boundary) |
ADDR_NOT_MAPPED |
COUNT_ERROR (Byte count is not a multiple of 4) |
PARAM_ERROR |
CODE_READ_PROTECTION_ENABLED
Description
This command is used to read data from RAM.
Example
"R 1073741824 4<CR><LF>" reads 4 bytes of data from address 0x4000 0000.