通信设计应用
Jumper | Position | Function |
JU1 |
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JU3 |
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JU4 |
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JU5 |
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JU6 |
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JU7 |
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Pin | MAX195 | TMS320 | Pin | MAX195 | TMS320 |
1 |
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3 |
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5 |
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7 |
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9 |
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.sect "vectors" reset .word init int0 .word init int1 .word init int2 .word init int3 .word init xint0 .word init rint0 .word init xint1 .word init rint1 .word init tint0 .word init tint1 .word init dint .word init .data STCK .word 0809F00H ; initial stack pointer CTRL .word 0808000H ; peripheral interface base address HOST_DATA .word 0804000H ; host data port address IOF_AMASK .set 0000EH ; clear all XF1 bits in IOF register IOF_SET_XF1 .set 00060H ; make XF1 pin an output; value = 1 IOF_RESET_XF1 .set 00020H ; make XF1 pin an output; value = 0 IOF_INPUT_XF1 .set 00080H ; make XF1 pin an input; read its value FS_AMASK .set 0F0FFH ; mask for an FS pin SET_FS .set 00600H ; make FS a high output RESET_FS .set 00200H ; make FS a low output GET_FS .set 00800H ; input mask for FS pin D_AMASK .set 0FF0FH ; mask for a Data pin SET_D .set 00060H ; make D a high output RESET_D .set 00020H ; make D a low output GET_D .set 00080H ; input mask for D pin CLK_AMASK .set 0FFF0H ; mask for a CLK pin SET_CLK .set 00006H ; make CLK a high output RESET_CLK .set 00002H ; make CLK a low output GET_CLK .set 00008H ; input mask for CLK pin Serial Port Global Control Register SerGlob1 .word 08100280H 08000000H: RRESET - reset / enable the receiver 0080H: RCLKSRCE - use internal receive clock (CLKR pin is an output) 0200H: RVAREN - Receiver Variable Data Rate 00100000H: RLEN = 2 bytes (16 bits) Pin Assignment Register for FSX, CLKX, DX SerPrtX1 .word 00H assign CLKX pin to general I/O make CLKX an input assign DX pin to general I/O make DX an input assign FSX pin to general I/O make FSX an input Pin Assignment Register for FSR, CLKR, DR SerPrtR1 .word 0111H 0001H: assign CLKR pin to serial port clock 0010H: assign DR pin to serial port receive data 0100H: assign FSR pin to serial port frame start Serial Port Timer Global Control Register SerTim1 .word 03C0H XHLD 0=hold transmit timer XC/P 0=pulse mode XCLKSRC 0=CLKX pin increments the counter 0040H: RGO=1 -- start the receive timer 0080H: RHLD 1=run receive timer 0100H: RC/P 1=clock (50% duty cycle) 0200H: RCLKSRC 1=use 7.5MHz time base (30MHz system clock/4) Serial Port Timer Period Register SerTim1Val .word 040000H 0 H: Transmit Counter Period 4 H: Receive Counter Period Receive Timer Period = 4 = 0.9375MHz .text init LDI 0,ST ; initialize status register LDI 0,DP ; point data page pointer into rom LDI @STCK,SP ; initialize stack pointer ; start with XF1 high ; LDI IOF,R1 ; get XF1 settings AND IOF_AMASK,R1 ; don't touch XF0 settings OR IOF_SET_XF1,R1 ; make XF1 output a high value LDI R1,IOF ; write new XF1 settings ; initialize serial port ; LDI @CTRL,AR0 ; peripheral interface address LDI @HOST_DATA,AR1 ; host interface address LDI @SerTim1Val,R0 STI R0,*+AR0(86) ; serial ch1 timer period LDI @SerGlob1,R0 STI R0,*+AR0(80) ; serial global register LDI @SerPrtX1,R0 STI R0,*+AR0(82) ; serial transmit control register LDI @SerPrtR1,R0 STI R0,*+AR0(83) ; serial receive control register LDI @SerTim1,R0 STI R0,*+AR0(84) ; serial ch1 timer register XF1 signal is named Active-Low CONV to MAX195 EVKIT This is how we set XF1: LDI IOF,R1 ; get XF1 settings AND IOF_AMASK,R1 ; don't touch XF0 settings OR IOF_SET_XF1,R1 ; make XF1 output a high value LDI R1,IOF ; write new XF1 settings This is how we clear XF1: LDI IOF,R1 ; get XF1 settings AND IOF_AMASK,R1 ; don't touch XF0 settings OR IOF_RESET_XF1,R1 ; make XF1 output a low value LDI R1,IOF ; write new XF1 settings next_sample: generate conversion start pulse LDI IOF,R1 ; get XF1 settings AND IOF_AMASK,R1 ; don't touch XF0 settings OR IOF_RESET_XF1,R1 ; make XF1 output a low value LDI R1,IOF ; write new XF1 settings AND IOF_AMASK,R1 ; don't touch XF0 settings OR IOF_SET_XF1,R1 ; make XF1 output a high value LDI R1,IOF ; write new XF1 settings wait until serial receive is complete loop LDI *+AR0(80),R2 ; read global control register AND 01H,R2 ; test the receiver ready bit BZ loop ; loop until data is received get the received data LDI *+AR0(92),R3 ; copy received data into R3 this demo application does no processing -- it just makes the value available to the TMS320C3X EVM's host. STI R3,*+AR1(0) ; send R3 to host LDI 100,R0 ; delay wait_loop: SUBI 1,R0 BNZ wait_loop BR @next_sample ; this program runs forever .end
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