MXSIGDM Microchip Technology, MXSIGDM Datasheet - Page 36

• Manufacturer Part Number: MXSIGDM
• Description: BOARD DEMO PICTAIL MIXED SIGNAL
• Manufacturer: Microchip Technology
• Series: PICtail™r

Specifications of MXSIGDM

• Main Purpose: Mixed Signal for MCU: ADC, DAC,
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: TX132x,MCP330x,320x,494x,3221,3201,1525,1541
• Primary Attributes: 3 ADCs, 3 DACs, 2 Voltage References, 5V LDO
• Secondary Attributes: DIP Switches, 2 LEDs, PIC16F767
• Processor To Be Evaluated: TC132x, MCP330x, MCP320x, MCP492x, MCP3221, MCP3021, MCP15x
• Interface Type: I2C, SPI
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

; OUTPUT
;
; THEORY OF OPERATION - CHOOSING # OF STEPS
; Using the above #s:
;
;
;
;
;
; These numbers need to be taken into consideration when choosing Fosc
; and the # of steps.
; more steps (doesn’t have to be 2^X # of steps) and the distortion
; caused by not executing the minimum loop very often.
; model this with most mathematical software packages to determine
; what is best for their system.
;
;*************************************************************************
DTMF
F_Low
F_Low_Rolling
F_Low_Step
F_Low_Out
F_High
F_High_Rolling
F_High_Step
F_High_Out
DTMF_Out
ToneLength
Key_Value
DTMF_SUB
;
; Conditional Assembly Control Words
;
#DEFINE Fosc_8000000
#DEFINE Fosc_4000000
#DEFINE Fosc_3570000
#DEFINE ToneLength_150
#DEFINE ToneLength_100
#DEFINE ToneLength_50
#DEFINE _32_steps
#DEFINE _16_steps
#DEFINE _32_steps
#DEFINE _16_steps
;
;*************************************************************************
; This is a 32 level lookup table of a 7 bit SINE wave
DS51523A-page 32
GLOBAL F_Low, F_Low_Rolling,F_Low_Step, F_Low_Out, F_High, F_High_Rolling
GLOBAL F_High_Step, F_High_Out, DTMF_Out, ToneLength, Key_Value
GLOBAL Tone, Repeat_tone
EXTERN DAC_MSB, DAC_LSB, WriteToMCP492X
if Fosc_8000000
endif
if Fosc_4000000 | Fosc_3570000
endif
if
Minimum loop = 17 cycles
Maximum loop = 46 cycles
Maximum Low distortion = 5 + 22 + 5 = 32
Maximum High distortion = 5 + 19 + 5 = 29
_32_steps
;No = 0, Yes = 1
- 5 cycles
CODE
UDATA
RES 1 ;# of cycles for the low frequency
RES 1 ;last value of TMR0 when F_Low_Out was updated
RES 1 ;SINE table index
RES 1 ;Output duty cycle for F_Low
RES 1 ;# of cycles for the high frequency
RES 1 ;last value of TMR0 when F_High_Out was updated
RES 1 ;SINE table index
RES 1 ;Output duty cycle for F_High
RES 1 ;Output for DAC
RES 1 ;# of F_High cycles used for delay
RES 1 ;what # to dial?
Obviously, there is a balance between adding
1 ;8MHz oscillator
0 ;4MHz oscillator
0 ;3.57MHz oscillator
0 ;150 ms tone per subroutine call
0 ;100 ms tone per subroutine call
1 ;50 ms tone per subroutine call
0 ;32 steps per cycle
1 ;16 steps per cycle
0 ;32 steps per cycle
1 ;16 steps per cycle
The user could
 2004 Microchip Technology Inc.