NXP Semiconductors LPC24XX UM10237 - Manual (Page 685)

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User manual Rev. 04 — 26 August 2009 685 of 792
NXP Semiconductors
UM10237
Chapter 30: LPC24XX Flash memory programming firmware
9.3 Echo
9.4 Write to RAM
The host should send the data only after receiving the CMD_SUCCESS return code. The
host should send the check-sum 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 should be of the actual number of bytes sent.
The ISP command handler compares it with the check-sum of the received bytes. If the
check-sum matches, the ISP command handler responds with "OK" to
continue further transmission. If the check-sum does not match, the ISP command
handler responds with "RESEND". In response the host should retransmit the
bytes.
9.5 Read Memory
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
Table 607. ISP Echo command
Command A
Input Setting: ON = 1 | OFF = 0
Return Code CMD_SUCCESS |
PARAM_ERROR
Description The default setting for echo command is ON. When ON the ISP command handler
sends the received serial data back to the host.
Example "A 0" turns echo off.
Table 608. 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.
Example "W 1073742336 4" writes 4 bytes of data to address 0x4000 0200.