ST7PSCR1E4M1/XXX View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST7PSCR1E4M1/XXX

8-BIT LOW-POWER, FULL-SPEED USB MCU WITH 16K FLASH, 768 RAM, SMARTCARD I/F, TIMER

STMicroelectronics 

ST7SCR

SMARTCARD INTERFACE (Cont’d)

SMARTCARD ELEMENTARY TIME UNIT REG-

ISTER (CRDETUx)

CRDETU1

Read/Write

Reset Value: 0000 0001 (01h)

7

0

COMP 0 0 0 0 ETU10 ETU9 ETU8

Bit 7 = COMP Elementary Time Unit Compensa-

tion.

0: Compensation mode disabled.

1: Compensation mode enabled. To allow non in-

teger value, one clock cycle is subtracted from

the ETU value on odd bits. See Figure 30.

GUARDTIME REGISTER (CRDGTx)

CRDGT1

Read/Write

Reset Value: 0000 0000 (00h)

7

0

0

0

0

0

0

0

0 GT8

CRDGT0

Read/Write

Reset Value: 0000 1100 (0Ch)

7

0

GT7 GT6 GT5 GT4 GT3 GT2 GT1 GT0

Bit [6:3] = Reserved

Bits 2:0 = ETU [10:8] ETU value in card clock cy-

cles.

Writing CRDETU1 register reloads the ETU coun-

ter.

CRDETU0

Read/Write

Reset Value: 0111 0100 (74h)

7

0

ETU7 ETU6 ETU5 ETU4 ETU3 ETU2 ETU1 ETU0

Software writes the Guardtime value in this regis-

ter. The value is loaded at the end of the current

Guard period.

GT: Guard Time: Minimum time between two con-

secutive start bits in transmission mode. Value ex-

pressed in Elementary Time Units (from 11 to

511).

The Guardtime between the last byte received

from the card and the next byte transmitted by the

reader must be handled by software.

Bits 7:0 = ETU [7:0] ETU value in card clock cy-

cles.

Note: The value of ETU [10:0] must in the range

12 to 2047. To write 2048, clear all the bits.

65/102

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