UT82CRH51AC-36WCX データシートの表示（PDF） - Aeroflex UTMC

部品番号

コンポーネント説明

メーカー

UT82CRH51AC-36WCX

UT82CRH51A USART

Aeroflex UTMC 

TRANSMITTER OUTPUT

TxD

START

MARKING

BIT

RECEIVER INPUT

RxD

START

BIT

D0 D1 --------------Dx

DATA BITS

Generated by

UT82CRH51A

PARITY BITS

STOP BITS

DOES NOT APPEAR ON

D0 D1 --------------Dx

THE DATA BUS

DATA BITS

PARITY BITS

STOP BITS

TRANSMISSION FORMAT

PROGRAMMED CHARACTER

LENGTH

CPU BYTE (5-8 BITS/CHAR)

DATA CHARACTER

START

BIT

RECEIVE FORMAT

START

BIT

ASSEMBLED SERIAL DATA OUTPUT (TxD)

DATA CHARACTER PARITY BITS

STOP BITS

SERIAL DATA INPUT (RxD)

DATA CHARACTER PARITY BITS

STOP BITS

CPU BYTE (5-8 BITS/CHAR)

DATA CHARACTER

Figure 10. Asynchronous Mode

*Note: If character length is defined

as 5,6 or 7 bits, the unused bits are

set to "ZERO"

2.2.7 Synchronous Mode (Receive)

In this mode, character synchronization can be internally or ex-

ternally achieved. If the SYNC mode has been programmed, an

ENTER HUNT command should be included in the first com-

mand instruction word written. Data on the RxD pin is then

sampled on the rising edge of RxC. The content of the Rx buffer

is compared at every bit boundary with the first SYNC character

until a match occurs. If the UT82CRH51A has been pro-

grammed for two SYNC characters, the subsequent received

character is also compared; when both SYNC characters have

been detected, the USART ends the HUNT mode and is in char-

acter synchronization. The SYNDET pin is then set high and is

reset automatically by a STATUS READ. If parity is pro-

grammed, SYNDET will not be set until the middle of the parity

bit instead of the middle of the last data bit.

In the external SYNC mode, synchronization is achieved by ap-

plying a high level of the SYNDET pin, thus forcing the

UT82CRH51A out of the HUNT mode. The high level can be

removed after one RxC cycle. An ENTER HUNT command has

no effect in the asynchronous mode of operation.

Parity error and overrun error are both checked in the same way

as in the Asynchronous Rx mode. Parity is checked when not in

HUNT, regardless of whether the Receiver is enabled or not

(Figure 12).

The CPU can command the receiver to enter the HUNT mode if

synchronization is lost. This will also set all the used character

bits in the buffer to a "one", thus preventing a possible false

SYNDET caused by data that happens to be in the Rx Buffer at

ENTER HUNT time. Note: The SYNDET F/F is reset at each

Status Read regardless of whether internal or external sync has

been programmed. This does not cause the UT82CRH51A to

return to the HUNT mode. When the SYNC mode but not in

HUNT, Sync Detection is still functional, but only occurs at the

"known" word boundaries. Thus, if one Status Read indicates

SYNDET and a second Status Read also indicates SYNDET,

then the programmed SYNDET characters have been received

since the previous Status Read. (If double character sync has

been programmed, then both sync characters have been contig-

uously received to gate a SYNDET indication.) When external

SYNDET mode is selected, internal Sync Detection is disabled,

and the SYNDET F/F may be set at any bit boundary (figure 13).

8

Share Link: