HT56RB688_13 datasheet(71/164 Pages) HOLTEK

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· SPI Interface Operation

The SPI interface is a full duplex synchronous serial data link. It is a four line interface with pin

names SDIn, SDOn, SCKn and SCSn where n stands for 0 and 1 respectively. Pins SDIn and SDOn

are the Serial Data Input and Serial Data Output lines, SCKn is the Serial Clock line and SCSn is the

Slave Select line. As the SPI interface pins are pin-shared with normal I/O pins and with the I2C

function pins, the SPI interface must first be enabled by selecting the SIMn enable configuration

options and setting the correct bits in the SIMnCTL0/SIMnCTL2 register. After the SIMn

configuration option has been configured it can also be additionally disabled or enabled using the

SIMnEN bit in the SIMnCTL0 register. Communication between devices connected to the SPI

interface is carried out in a slave/master mode with all data transfer initiations being implemented by

the master. The Master also controls the clock signal. As each SIM only contains a single SCS pin,

only one slave device can be utilized for each SIM.

The SPI function in this device offers the following features:

¨ Full duplex synchronous data transfer

¨ Both Master and Slave modes

¨ LSB first or MSB first data transmission modes

¨ Transmission complete flag

¨ Rising or falling active clock edge

¨ WCOLn and CSENn bit enabled or disable select

The status of the SPI interface pins is determined by a number of factors such as whether the device

is in the master or slave mode and upon the condition of certain control bits such as CSENn,

SIMnEN and SCSn. In the table I, Z represents an input floating condition. There are several

configuration options associated with the SPI interface. One of these is to enable the SIMn function

which selects the SIMn pins rather than normal I/O pins. Note that if the configuration option does

not select the SIMn function then the SIMnEN bit in the SIMnCTL0 register will have no effect.

Another two SIMn configuration options determine if the CSENn and WCOLn bits are to be used.

Configuration Option

Function

SIMn Function

SIMn interface or I/O pins

SPI CSENn bit

Enable/Disable

SPI WCOLn bit

Enable/Disable

SPI Interface Configuration Options

HT56RB688

TinyPowerTM A/D type Smart Card OTP MCU

with LCD, DAC, ISO 7816 and USB Interfaces

Rev. 1.10

April 15, 2013

HT56RB688 Datasheet(PDF) 71 Page - Holtek Semiconductor Inc