Print a CHARACTER

PrintCHAR

Purpose:	Output a single character (CHAR) to the serial port.
Assumes:	Values less than 7 are unprintable, as is the value 255.
Passed:	R24	CHAR	cValue	the character to print (or enbuffer)
Returns:	R24	CHAR	cValue	the same cValue that was passed in R24, unchanged
Alters:	Only the FLAGs (SREG) and the COM1 Transmit buffer

Example:
.ORG 0x1000 CSZ_SpEqSp = 0x3AD2 ; FLASH address of the string " = ", NULL OutputOneCHAR: LDI R21, 1 << BIT_PV_HEX ; BIT_PV_HEX = 1, in case parsing is skipped ADIW R26, 0 ; If there is no command tail, don't try to BREQ ASaveDataCHAR ; parse anything starting at SRAM address 0! MOVW R24, R26 ; Move the command tail pointer to R25:R24 in CALL AParseValue ; order to parse any value found there MOV R24, R22 ; Use parsed value's LSByte (or 0) to R24 SaveDataCHAR: MOV R26, R24 ; Preserve the CHAR to be output SBRS R21, BIT_PV_HEX ; If a value was input in decimal notation, CALL APrint0xHexBYTE ; print it in standard hex notation SBRC R21, BIT_PV_HEX ; But if it was input in hexadecimal format, CALL APrintBYTE ; print it in decimal notation instead LDI R25, CSZ_SpEqSp >> 8 ; Point to the delimiter string, which is LDI R24, CSZ_SpEqSp & 0xFF ; already contained in the FLASH memory CALL APrintFLASHASCIIz ; Print the NULL terminated string LDI R24, '"' ; To highlight the CHAR printed, surround it CALL APrintCHAR ; in double quotes, so print the first one MOV R24, R26 ; Restore the CHAR to be printed CALL APrintCHAR LDI R24, '"' ; Normally, a single quote would be used for CALL APrintCHAR ; a CHAR, but ''' is somewhat confusing JMP APrintNewLine ; Print Carriage Return, Line Feed & exit

Test it:
m>@ 4096 ; With a command tail but no parameter 0x00 = "" m>@ 4096 0 = "" m>@ 4096 1 ; No output for CHAR values 0 through 7 0x01 = "" m>@ 4096 9 ; This is the TAB character 0x09 = " " m>@ 4096 10 ; This is the "Line Feed" character 0x0A = " " m>@ 4096 0x20 32 = " " m>@ 4096 0x41 65 = "A" m>@ 4096 122 0x7A = "z" m>

Notes: This is a "wrapper" around the COM1_Write1CHAR routine, which does not preserve R25, R26, R27, R30, or R31.

Any CHAR value from 7 through 254 is output, so non-standard ASCII characters (those above 127) may be printed.

The value 255 (= 0xFF) is discarded since it likely was read from an area of uninitialized FLASH.
As with the other Print functions, this function can block.

Dropin:
(setup
code)
; Setup for the PrintCHAR() call: ; Passed: R24 CHAR cValue to print in binary format ; Returns: R24 CHAR cValue, unchanged ; Alters: the FLAGs and the COM1 Transmit Buffer

Also see: The System Functions PrintBYTE, Print0xPrefix, the PrintBYTE family, and the PrintWORD family.

Example:	.ORG 0x1000 CSZ_SpEqSp = 0x3AD2 ; FLASH address of the string " = ", NULL OutputOneCHAR: LDI R21, 1 << BIT_PV_HEX ; BIT_PV_HEX = 1, in case parsing is skipped ADIW R26, 0 ; If there is no command tail, don't try to BREQ ASaveDataCHAR ; parse anything starting at SRAM address 0! MOVW R24, R26 ; Move the command tail pointer to R25:R24 in CALL AParseValue ; order to parse any value found there MOV R24, R22 ; Use parsed value's LSByte (or 0) to R24 SaveDataCHAR: MOV R26, R24 ; Preserve the CHAR to be output SBRS R21, BIT_PV_HEX ; If a value was input in decimal notation, CALL APrint0xHexBYTE ; print it in standard hex notation SBRC R21, BIT_PV_HEX ; But if it was input in hexadecimal format, CALL APrintBYTE ; print it in decimal notation instead LDI R25, CSZ_SpEqSp >> 8 ; Point to the delimiter string, which is LDI R24, CSZ_SpEqSp & 0xFF ; already contained in the FLASH memory CALL APrintFLASHASCIIz ; Print the NULL terminated string LDI R24, '"' ; To highlight the CHAR printed, surround it CALL APrintCHAR ; in double quotes, so print the first one MOV R24, R26 ; Restore the CHAR to be printed CALL APrintCHAR LDI R24, '"' ; Normally, a single quote would be used for CALL APrintCHAR ; a CHAR, but ''' is somewhat confusing JMP APrintNewLine ; Print Carriage Return, Line Feed & exit
Test it:	m>@ 4096 ; With a command tail but no parameter 0x00 = "" m>@ 4096 0 = "" m>@ 4096 1 ; No output for CHAR values 0 through 7 0x01 = "" m>@ 4096 9 ; This is the TAB character 0x09 = " " m>@ 4096 10 ; This is the "Line Feed" character 0x0A = " " m>@ 4096 0x20 32 = " " m>@ 4096 0x41 65 = "A" m>@ 4096 122 0x7A = "z" m>
Notes:	This is a "wrapper" around the COM1_Write1CHAR routine, which does not preserve R25, R26, R27, R30, or R31.
	Any CHAR value from 7 through 254 is output, so non-standard ASCII characters (those above 127) may be printed.
	The value 255 (= 0xFF) is discarded since it likely was read from an area of uninitialized FLASH.
	As with the other Print functions, this function can block.

Dropin: (setup code)	; Setup for the PrintCHAR() call: ; Passed: R24 CHAR cValue to print in binary format ; Returns: R24 CHAR cValue, unchanged ; Alters: the FLAGs and the COM1 Transmit Buffer
Also see:	The System Functions PrintBYTE, Print0xPrefix, the PrintBYTE family, and the PrintWORD family.