Implement RAPI Sequence ID support #3
Description
For integrity's sake, I recommend that you implement RAPI sequence ID support, in order to ensure that replies don't get out of sync w/ commands. You can review my code in RapiSender.cpp in the ESP code for reference.
From rapi_proc.h of the OpenEVSE firmware:
Command format:
$cc pp pp .. :ss^xk\r
\r = carriage return = 13d = 0x0D
cc = 2-letter command
pp = parameters
xk = 2-hex-digit checksum - 8-bit XOR of all characters before '^'
ck = 2-hex-digit checksum - 8-bit sum of all characters before '*'
ss = optional 2-hex-digit sequence id - response will echo the sequence id
so that receiver can verify that the response matches the command
ss CANNOT be 00, which is reserved as an invalid value
response format:
$OK [optional parameters] [:ss]^xk\r - success
$NK [optional parameters] [:ss]^xk\r - failure
xk = 2-hex-digit checksum - 8-bit XOR of all characters before '^'
ss = optional 2-hex-digit sequence ID which was sent with the command
only present if a sequence ID was send with the command