18

LTC1402

;

————————Buffered Receive Interrupt Routine —————————

breceive:

ifr = #10h

; clear interrupt flags

TC = bitf(@BSPCE,#4000h)

; check which half (bspce(bit14)) of buffer

if (NTC) goto bufull

; if this still the first half get next half

bspce = #(2023h + 08000h)

; turn on halt for second half (bspce(bit15))

return_enable

;

———————mask and shift input data after 2k buffer is full——-

bufull:

b = *ar3+ << -2

; load acc b with BSP buffer and shift right 2

b = #00FFFh & b

; mask out the REF bit and the 3 other tristate bits

b = #00800h ^ b

; invert BIPOLAR MSB. Comment this line in UNIPOLAR mode

*ar2+ = data(#0bh)

; store B to out buffer and advance AR2 pointer

TC = (@ar2 == #02000h) ; output buffer is 2k starting at 1800h

if (TC) goto start

; restart if out buffer is at 1fffh

goto bufull

;

—————————dummy bsend return————————————

bsend return_enable

;this is a dummy return to define bsend

;in vector table below

;

——————————— end ISR ——————————————

;initialize buffered serial port

**********************************************************************

*

BSP initialization code for the ‘C54x DSKplus

*

*

for use with 1402 in standard mode

*

*

BSPC and SPC are the same in the ‘C542

*

**********************************************************************

ON

.set 1

OFF

.set !ON

YES

.set 1

NO

.set !YES

BIT_8

.set 2

BIT_10

.set 1

BIT_12

.set 3

BIT_16

.set 0

GO

.set 0x80

**********************************************************************

* This is an example of how to initialize the Buffered Serial Port (BSP).

* The BSP is initialized to require an external CLK and FSX for

* operation. The data format is 16-bits, burst mode, with autobuffering

* enabled.

*

*

*****************************************************************************************************

*Timing at BSP pins in DSKPLUS TMS320c542 board with inverters at BCLKR and BFSR.

*

*BFSR Pin JP1-20 ~\___/~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\___/~~~~~~~~~~*

*BCLKR Pin JP1-14 _/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/

*

*BDR Pin JP1-26 -_—_—<REF-B11-B10-B09-B08-B07-B06-B05-B04-B03-B02-B01-B00>—_—_—<REF-B11-

*

*CLKIN Pin JP5-09 ~~~~~\_______/~~~~~~~\_______/~~~~~~~\_______/~~~~~~~\_______/~~~~~~~\_______/~~~~

*

*

*

*A 2 place right shift is needed to right justify the input data.

*

*The REF bit is also be masked in this example

*

*****************************************************************************************************

*

Loopback

.set

NO

;(digital looback mode?)

DLB bit

Format

.set

BIT_16

;(Data format? 16,12,10,8)

FO bit

IntSync

.set

NO

;(internal Frame syncs generated?)

TXM bit

IntCLK

.set

NO

;(internal clks generated?)

MCM bit

BurstMode

.set

YES

;(if BurstMode=NO, then Continuous)

FSM bit

CLKDIV

.set

3

;(3=default value, 1/4 CLOCKOUT)

PCM_Mode

.set

NO

;(Turn on PCM mode?)

FS_polarity

.set

NO

;(change polarity)YES=^^^\_/^^^, NO=___/^\___

CLK_polarity

.set

YES

;(change polarity)for BCLKR YES=_/^, NO=~\_

Frame_ignore

.set

!YES

;(inverted !YES -ignores frame)

XMTautobuf

.set

NO

;(transmit autobuffering)

RCVautobuf

.set

YES

;(receive autobuffering)

XMThalt

.set

NO

;(transmit buff halt if XMT buff is full)

RCVhalt

.set

NO

;(receive buff halt if RCV buff is full)

XMTbufAddr

.set

0x800

;(address of transmit buffer)

XMTbufSize

.set

0x000

;(length of transmit buffer)