Functional Description

SRAM

The 256 x 4 bits index SRAM and 128 x 4 bits data SRAM are 2 separate regions.

Index ROM

The 256 x 8 bits index ROM can be used as a 4-bit mode or an 8-bit mode.

I/O ports

The IOA port can be selected by software separately as input or output, and with/without internal pull-low and

different chattering clocks in order for HALT release/ interrupt trigger to reduce the bounce of key_scan:

PH6: 512Hz PH8:128Hz PH10: 32Hz

The pull-low of the IOA will be masked off for those pins defined as output pins.

The IOA port can be used as a pseudo serial output port.

The IOB port can be selected by software separately as input or output.

The IOC port can be selected by software separately as input or output, and with/without internal pull-low and

different chattering clocks in order for HALT release/ interrupt trigger to reduce the bounce of key_scan.

The IOD port can be selected by software separately as input or output.

The IOD port can be used as a pseudo serial output port.

The initial state of all I/O ports is standard input state and IOA, C have pull-low device.

Before setting some pins from input to output, you can execute the output function to ensure their output value.

The S ports are input pins that contain pull-low. The L_L_H resistor can be selected by mask option and

different chattering clocks in the same manner as the IOA, C ports.

Resistor to frequency converter

We use an RC oscillation circuit and a 16-bit counter to calculate the relative resistance of temperature and

humidity sensor. The diagram is shown below:

RT

RH

RR

CX

ELP

RHM

Rref

CX

ENX

EHM

FIN

ERR

ENX

FIN

Freq.

CL

LD

16-Bit Counter

4-Bit Data Bus

Freq.

CL

LD

TMS

PH9

MRF

Timer & R/F

Controller

RTP

There are two types of methodology for measuring the input frequency: first, set FIN (i.e. CX) as the clock

input, using timer 2 as interval control or using software to directly control the interval. Second, if the FIN (CX)

frequency is too low, either because of a poor resolution for a fixed interval or a longer interval for better

Preliminary

8

Ver. 0.0