I'm sending NCO values from one PIC to another. The Comm protocol requires 2 bytes per NCO1INCx register; 1st identifies it, 2nd is the NCO1INCx value. Finally there is a "Start" command byte sent. I noticed shooting for 2.4 MHz that I only got 564 Hz. However, if I turn the NCO Module Off, then On again, I get the 2.4 MHz. Here is the code for the Receiver:
There is a slight delay in getting the 2.4 MHz output, which for this application is acceptable. Just wondering if I might have overlooked something simple.Code:DEFINE OSC 8
DEFINE HSER_RCSTA 90h ;Enable serial port & continuous receive
DEFINE HSER_TXSTA 02h ;Disable transmit, BRGH = 0
DEFINE HSER_CLROERR 1 ;Clear overflow automatically
DEFINE HSER_BAUD 9600
;Configurations:
#CONFIG
__config _CONFIG1, _FEXTOSC_OFF & _RSTOSC_HFINT32 & _CLKOUTEN_OFF & _CSWEN_OFF & _FCMEN_ON
__config _CONFIG2, _MCLRE_OFF & _PWRTE_OFF & _WDTE_ON & _LPBOREN_OFF & _BOREN_ON & _BORV_LOW & _PPS1WAY_OFF & _STVREN_ON & _DEBUG_OFF
__config _CONFIG3, _WRT_OFF & _LVP_OFF
__config _CONFIG4, _CP_OFF & _CPD_OFF
#ENDCONFIG
;Aliases:
;Prb VAR LATA.0 ;HF Generator Driver for Probes
;RX VAR PORTA.1 ;USART Receive
;TX VAR PORTA.2 ;USART Transmit
;MCLR VAR PORTA.3 ;!MCLR
;NC VAR PORTA.4 ;
;Wand VAR LATA.5 ;HF Generator Driver for IR LEDs
;Special Function Registers:
OSCCON1 = %00000010 ;INTTOSC, 1:4 Divider, 8 MHz
OSCFRQ = %00000011 ;8 MHz
TRISA = %00001110
ANSELA = 0
WPUA = 0
PPSLOCK = $55
PPSLOCK = $AA
PPSLOCK = 0 ;Unlock PPS
;RA0PPS = %00011101 ;Sets NCO Output to RA0, Pin 7
;RA5PPS = %00011101 ;Sets NCO Output to RA5, Pin 2
RA2PPS = %00010100 ;Sets USART TX to RA2, Pin 5
RXPPS = %00000001 ;Sets USART RX to RA1, Pin 6
PPSLOCK = $55
PPSLOCK = $AA
PPSLOCK = 1 ;Lock PPS
NCO1CON = %10000000
NCO1CLK = 1 ;NCO1 Clock = Fosc
PMD0 = %01000101
PMD1 = %00000101
PMD2 = %01100110
PMD3 = %01110011
PMD4 = %00000000
PMD5 = %00000111
VREGCON = 3 ;Lowest Power in SLEEP Mode
CPUDOZE = %10100100
INTCON = %01000000
TX1STA = %00000010 ;$02
RC1STA = %10010000 ;$90
BAUD1CON = %00000010
SP1BRGL = $0C ;Decimal 12, Yields 9600 BAUD
PIE1.5 = 1 ;RCIE, USART Receive Flag
;Variables:
NcoL VAR BYTE BANK0 SYSTEM ;USART NCO1INCL Value
NcoH VAR BYTE BANK0 SYSTEM ;USART NCO1INCH Value
NcoU VAR BYTE BANK0 SYSTEM ;USART NCO1INCU Value
Rec VAR BYTE BANK0 SYSTEM ;USART Receive Register Value
;Constants:
Begin CON %10010000 ;USART Command to Start NCO, $90
Halt CON %10010001 ;USART Command to Stop NCO, $91
IR CON $92 ;USART Command to Set NCO Output to LATA.5
Prb CON $93 ;USART Command to Set NCO Output to LATA.0
NcoL_Val CON %10000001 ;USART Command, Following is NcoL, $81
NcoH_Val CON %10000010 ;USART Command, Following is NcoH, $82
NcoU_Val CON %10000011 ;USART Command, Following is NcoU, $83
;Labels:
Main:
PIR1.5 = 0
PAUSE 50
DO
DO
LOOP WHILE PIR1.5 = 0
GOSUB Orders
LOOP
Run:
DO
IF PIR1.5 = 1 THEN
GOSUB Orders
ENDIF
PAUSE 1
LOOP
Slumber:
NCO1CON.7 = 0
@ DOZE
@ NOP
GOTO Main
Orders:
HSERIN [Rec]
; Rec = RC1REG
SELECT CASE Rec
CASE IS = $81
HSERIN [NcoL]
NCO1INCL = NcoL
CASE IS = $82
HSERIN [NcoH]
NCO1INCH = NcoH
CASE IS = $83
HSERIN [NcoU]
NCO1INCU = NcoU
CASE IS = $90
STKPTR = STKPTR - 1
PIR1.5 = 0
NCO1CON.7 = 1. ;Turn NCO On
PAUSE 500
NCO1CON.7 = 0. ;Turn NCO Off
PAUSE 500
NCO1CON.7 = 1. ;Turn NCO On
GOTO Run
CASE IS = $91
STKPTR = STKPTR - 1
PIR1.5 = 0
GOTO Slumber
CASE IS = $92
PPSLOCK = $55
PPSLOCK = $AA
PPSLOCK = 0 ;Unlock PPS
RA5PPS = %00011101 ;Sets NCO Output to RA5, Pin 2
PPSLOCK = $55
PPSLOCK = $AA
PPSLOCK = 1 ;Lock PPS
TRISA.0 = 1 ;Shuts Down Alt Pin LATA.0
CASE IS = $93
PPSLOCK = $55
PPSLOCK = $AA
PPSLOCK = 0 ;Unlock PPS
RA0PPS = %00011101 ;Sets NCO Output to RA0, Pin 7
PPSLOCK = $55
PPSLOCK = $AA
PPSLOCK = 1 ;Lock PPS
TRISA.5 = 1 ;Shuts Down Alt Pin LATA.5
END SELECT
PIR1.5 = 0
RETURN
