A fast and easily customised operating system
for ARM devices
OS_SerialOp 4
Programmer's Reference Manuals
» Part 15 – SWI Calls
» OS
» OS_SerialOp
» OS_SerialOp 4
OS_SerialOp 4
(SWI &57)
| Entry | |
|---|---|
| R0 | 4 |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Character received (if C flag cleared), or |
| preserved (if C flag set) i.e. no character available in buffer to read) |
Use
The purpose of this call is to remove a character from the serial input buffer if one is present.
Notes
If removing a character leaves the input buffer with more free space than are specified by OS_Byte 203, then the transmitting device is re-enabled in the way specified by the serial port state (as set by OS_SerialOp 0).