HT56RB27 datasheet(68/153 Pages) HOLTEK

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2C Registers

There are three control registers associated with the I

2C bus, SIMnCTL0, SIMnCTL1 and SIMnAR

and one data register, SIMnDR. The SIMnDR register, which is shown in the above SPI section, is

used to store the data being transmitted and received on the I

2C bus. Before the microcontroller writes

data to the I

2C bus, the actual data to be transmitted must be placed in the SIMnDR register. After the

data is received from the I

2C bus, the microcontroller can read it from the SIMnDR register. Any

transmission or reception of data from the I

2C bus must be made via the SIMnDR register. Note that the

SIMnAR register also has the name SIMnCTL2 which is used by the SPI function. Bits SIMIDLE,

SIMnEN and bits SIMn_0~SIMn_2 in register SIMnCTL0 are used by the I

2C interface. The

SIMnCTL0 register is shown in the above SPI section.

· SIMIDLE

When the device is in the IDLE mode, the SIMIDLE bit has no effect if the I

2C interface is selected to

be used. Setting the bit high only allows the clock source of the Peripheral clock PCLK, which is

selected to come from the divided system clock, to keep active when the device is in the IDLE mode.

It will maintain the Peripheral clock PCLK output active if the PCKEN bit is set to 1 in IDLE mode.

Clearing the bit to zero disables the PCLK output when the device is in the IDLE mode. This SPI/I

IDLE mode control bit SIMIDLE is located at CLKMOD register bit4.

· SIMnEN

The SIMnEN bit is the overall on/off control for the I

2C interface. When the SIMnEN bit is cleared to

zero to disable the I

2C interface, the SDAn and SCLn lines will be in a floating condition and the I2C

operating current will be reduced to a minimum value. In this condition the pins can be used as

normal I/O functions. When the bit is high the I

2C interface is enabled. The SIMn configuration

option must have first enabled the SIMn interface for this bit to be effective. Note that when the

SIMnEN bit changes from low to high the contents of the I

2C control registers will be in an unknown

condition and should therefore be first initialised by the application program.

· SIMn_0~SIMn_2

These bits setup the overall operating mode of the SIMn function. To select the I

2C function, bits

SIMn_2~SIMn_0 should be set to the value 110.

Rev. 1.20

April 26, 2013

HT56RB27

TinyPowerTM A/D Type Smart Card OTP MCU

with DAC, ISO 7816 and USB Interfaces

I 2 C D a t a R e g i s t e r

( S I M n D R )

S l a v e A d d r e s s R e g i s t e r

( S I M n A R )

S h i f t R e g i s t e r

D i r e c t i o n C o n t r o l

A d d r e s s M a t c h

H A A S n B i t

I 2 C I n t e r r u p t

D a t a i n L S B

D a t a O u t M S B

T r a n s m i t / R e c e i v e

C o n t r o l U n i t

8 - b i t D a t a C o m p l e t e

D e t e c t S t a r t o r S t o p

D a t a B u s

A d d r e s s

C o m p a r a t o r

E n a b l e / D i s a b l e A c k n o w l e d g e

R e a d / w r i t e S l a v e

S R W n B i t

H B B n B i t

H T X n B i t

S C L n P i n

S D A n P i n

H C F n B i t

2C Block Diagram

HT56RB27 数据表(PDF) 68 Page - Holtek Semiconductor Inc

HT56RB27 数据表(HTML) 68 Page - Holtek Semiconductor Inc

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