Texas Instruments MSP50C614 manual Data

Implementation Details

;±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±

;called from C±±

;void oport(char Port, int Data)

;Writes Data to the I/O port specified by the letter Port.

;Example:

;oport('B', 0xAA); //Write 0xAA to port B. ;±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±± _oport

mov	a0, *r7 ± 4 ; port address
mov	a0~, *r7 ± 2	; data
add	a0, _out_port_access ± 'A' ; find the location in the table
mov	a0, *a0	; get the value of the label in the table
jmp	*a0	; jump to the label from the table
_prta
out	0x00, a0~	; write to PortA
ret
_prtb
out	0x08, a0~;	write to PortB
ret
_prtc
out	0x10, a0~	; write to PortC
ret
_prtd
out	0x18, a0~	; write to PortD
ret
_prte
out	0x20, a0~	; write to PortE
ret
_out_port_access		; table for table lookup
DATA	_prta
DATA	_prtb
DATA	_prtc
DATA	_prtd
DATA	_prte

;±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±

;±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±

;called from C±±

;int iport(char Port)

;Reads data from the I/O port specified by the letter Port.

;Example:

;int data = iport('F'); //Read port F. ;±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±± _iport

mov	a0, *r7 ± 2 ; port address
add	a0, _in_port_access ± 'A' ; find the location in the table
mov	a0, *a0	; get the value of the label in the table
jmp	*a0	; jump to the label from the table
_iprta
in	a0, 0x00	; read from PortA
ret
_iprtb
in	a0, 0x08	; read from PortB
ret

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