NXP Semiconductors LPC24XX UM10237 - Manual (Page 702)

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User manual Rev. 04 — 26 August 2009 702 of 792
NXP Semiconductors
UM10237
Chapter 31: LPC24XX On-chip bootloader for flashless parts
[1] ISP entry after reset uses the on chip IRC and PLL to run the device at CCLK = 14.748 MHz
6.3 Echo <setting>
6.4 Write to RAM <start address> <number of bytes>
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<CR><LF>" to
Return Code CMD_SUCCESS |
INVALID_BAUD_RATE |
INVALID_STOP_BIT |
PARAM_ERROR
Description This command is used to change the baud rate. The new baud rate is effective
after the command handler sends the CMD_SUCCESS return code.
Example "B 57600 1<CR><LF>" sets the serial port to baud rate 57600 bps and 1 stop bit.
Table 633. Correlation between possible ISP baudrates and CCLK frequency (in MHz)
ISP Baudrate .vs.
CCLK Frequency 9600 19200 38400 57600 115200 230400
10.0000 + + +
11.0592 + + +
12.2880 + + +
14.7456 [1] + + + + + +
15.3600 +
18.4320 + + +
19.6608 + + +
24.5760 + + +
25.0000 + + +
Table 632. ISP Set Baud Rate command
Command B
Table 634. 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<CR><LF>" turns echo off.