S e r i a l C o n t r o l l e r M o d u l e

 

 

 

 

 

 

 

 

 

 

 

Bits

Access

Mnemonic

Reset

Description

 

 

 

 

 

 

 

D20:19

R/W

TDCR

0

Transmit divide clock rate

 

 

 

 

00

1x clock mode (only NRZ or NRZI

 

 

 

 

 

allowed)

 

 

 

 

01

8x clock mode

 

 

 

 

10

16x clock mode

 

 

 

 

11

32x clock mode

 

 

 

 

Determine the oversampling multiplier for the

 

 

 

 

transmitter and receiver clocks.

 

 

 

 

If DPLL is not used and you are not using

 

 

 

 

UART, select the value 1x.

 

 

 

 

If DPLL is not used but you are using

 

 

 

 

UART, select 8x, 16x, or 32x (16x is

 

 

 

 

recommended).

 

 

 

 

In most applications, the TDCR and RDCR

 

 

 

 

configurations should match.

 

 

 

 

When DPLL is used in the application, the

 

 

 

 

selected TDCR/RDCR value is a function

 

 

 

 

of the transmitter encoding. NRZ and

 

 

 

 

NRZI modes can use the 1x configuration;

 

 

 

 

all other encoding must use 8x, 16x, or

 

 

 

 

32x configuration mode. 8x configuration

 

 

 

 

provides the highest data rate; 32x mode

 

 

 

 

provides the highest resolution.

 

 

 

 

The TMODE bit in the Serial Channel Bit-Rate

 

 

 

 

register is maintained for NET+ARM family

 

 

 

 

backward compatibility. When setting TDCR

 

 

 

 

or RDCR to a non-zero value, the TMODE must

 

 

 

 

be set to 1. When the TMODE, TDCR, and

 

 

 

 

RDCR fields are set to 0, the port defaults to

 

 

 

 

16x mode of operation.

 

 

 

 

 

D18

N/A

Reserved

N/A

N/A

Table 90: Serial Channel Bit-Rate register bit definition

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Digi NS7520 manual Tdcr, Transmit divide clock rate, If Dpll is not used and you are not using