© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual
Rev. 01 — 15 August 2005
299
Philips Semiconductors
UM10139
Volume 1
Chapter 21: Flash Memory
21.8.3 Echo
<setting>
21.8.4 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
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.
Table 291: Correlation between possible ISP baudrates and external crystal frequency (in
MHz)
ISP Baudrate .vs.
External Crystal Frequency
9600
19200
38400
57600
115200
230400
10.0000
+
+
+
11.0592
+
+
+
12.2880
+
+
+
14.7456
+
+
+
+
+
+
15.3600
+
18.4320
+
+
+
19.6608
+
+
+
24.5760
+
+
+
25.0000
+
+
+
Table 292: 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.