ELAN Home Systems EM78P458 - Manual (Page 35)

EM78P458/459
OTP ROM
(1) Write to the three bits (IMS2:IMS0) on the AD-CMP-CON1 register to define the characteristics
of R6: Digital I/O, analog channels, and voltage reference pin;
(2) Write to the ADCON register to configure AD module:
(a) Select A/D input channel ( ADAS2:ADAS0 );
(b) Select the proper gains by writing to the GCON register ( optional );
(c) Define A/D conversion clock rate ( CKR1:CKR0 );
(d) Set the ADPD bit to 1 to begin sampling.
(3) Put “ENI” instruction, if the interrupt function is employed.
(4) Set the ADRUN bit to 1.
(5) Wait for either the interrupt flag to be set or the ADC interrupt to occur.
(6) Read ADDATA, the conversion data register.
(7) Clear the interrupt flag bit (ADIF).
(8) For next conversion, go to Step 1 or Step 2 as required. At least 2 Tct is required before next
acquisition starts.
<Note>: To obtain an accurate value, it is necessary to avoid any data transition on I/O pins during
AD conversion.
2. The Demonstration Programs
; To define the general registers
R_0 == 0 ; Indirect addressing register
PSW == 3 ; Status register
PORT5 == 5
PORT6 == 6
R_F== 0XF ; Interrupt status register
; To define the control register
IOC50 == 0X5 ; Control Register of Port 5
IOC60 == 0X6 ; Control Register of Port 6
C_INT== 0XF ; Interrupt Control Register
This specification is subject to change without prior notice. 07.01.2003 (V1.3) 35