IV ANALOG BLOCK: A/D CONVERTER

I/O Pins of A/D Converter

Table 2.1 shows the pins used by the A/D converter.

Table 2.1 I/O Pins of A/D Converter

Pin name

I/O

Function

Function select bit

K52/#ADTRG

I

Input port / AD trigger

CFK52(D2)/K5 function select register(0x402C0)

K60/AD0

I

Input port / AD converter input 0

CFK60(D0)/K6 function select register(0x402C3)

K61/AD1

I

Input port / AD converter input 1

CFK61(D1)/K6 function select register(0x402C3)

K62/AD2

I

Input port / AD converter input 2

CFK62(D2)/K6 function select register(0x402C3)

K63/AD3

I

Input port / AD converter input 3

CFK63(D3)/K6 function select register(0x402C3)

AVDD

–

Analog reference voltage (+)

–

AVDD (analog power-supply pin)

AVDD is the power-supply pin for the analog circuit. The voltage level supplied to this pin must be AVDD = VDD.

Note: When the A/D converter is set to enabled state, a current flows between AVDD and VSS, and power is consumed, even when A/D operations are not performed. Therefore, when the A/D converter is not used, it must be set to the disabled state (default "0" setting of ADE(D2) in the A/D enable register (0x40244)).

AD[3:0] (analog-signal input pins)

The analog input pins AD3 (Ch.3) through AD0 (Ch.0) are shared with input port pins K63 through K60. Therefore, when these pins are used for analog input, they must be set for use with the A/D converter in the software. This setting can be made individually for each pin. At cold start, all these pins are set for input ports. The analog input voltage AVIN can be input in the range of VSS ≤ AVIN ≤ AVDD.

#ADTRG (external-trigger input pin)

This pin is used to input a trigger signal to start A/D conversion from an external source. Since this pin is shared with input port K52, it must be set for use with the A/D converter in the software before an external trigger can be applied to the pin. At cold start, this pin is set for an input port.

Method for setting A/D-converter input pins

At cold start, the #ADTRG and AD[3:0] pins all are set for input ports Kxx (function select bit CFKxx = "0"). When using these pins for the A/D converter, write "1" to the function select bit CFKxx.

At hot start, these pins retain their state from prior to the reset.

B-IV-2-2

EPSON

S1C33210 FUNCTION PART