NEC LCD3215 External Control Guide - Page 17

8. Asset Data read and write 8.1 Asset Data Read Request and reply This command is used in order to read Asset Data. 1) The controller requests the monitor to reply with Asset data. Header SOH-'0'-'A'-'0'-'A'-'0'-'A' Message STX-'C'-'0'-'0'-'B'-'0'-'0'-'2'-'0'-ETX Check code BCC Delimiter CR Header SOH (01h): Start Of Header '0' (30h): Reserved 'A' (41h): Monitor ID LCD3215/LCD4215 must be ASCII 'A' (41h). '0' (30h): Message sender is the controller 'A' (41h): Message type is "Command" '0'-'A' (30h, 41h): Message length is 10 bytes Message STX (02h): Start of Message 'C'-'0'-'0'-'B' (43h, 30h, 30, 42h): Asset read request command '0'-'0' (30h, 30h): Offset data from top of the Asset data. At first set 00h: Read data from the top of Asset data area. Secondly set 20h: Read data from the 32bytes offset point in the Asset data area. '2'-'0' (32h, 30h): Read out data length is 32bytes. Maximum readout length is 32bytes at a time. ETX (03h): End of Message Check code BCC: Block Check Code Refer to the section 4.5 "Check code" for a BCC calculation. Delimiter CR (0Dh): End of packet 2) The monitor replies Asset data to the controller. Header SOH-'0'-'0'-'A'-'B'-N-N Message STX-'C'-'1'-'0'-'B'Data(0)-Data(1)---Data(N)-ETX Check code BCC Delimiter CR Header SOH (01h): Start of Header '0' (30h): Reserved '0' (30h): Message receiver is the controller 'A' (41h): Monitor ID LCD3215/LCD4215 must be ASCII 'A' (41h). 'B' (42h): Message type is "Command reply" N-N: Message length Ex.) The byte data 20h is encoded to ASCII characters '2' and '0' (32h and 30h). Note.) This length is includes STX and ETX. Message STX (02h): Start of Message 'C'-'1'-'0'-'B' (43h, 31h, 30, 42h): Asset read reply command Data(0) - Data(N): Retuned Asset data. ETX (03h): End of Message Check code BCC: Block Check Code Refer to the section 4.5 "Check code" for a BCC calculation. Delimiter CR (0Dh): End of packet (17/37)