Specifications

AN93

Rev. 0.9 97

U87 SAM Synchronous Access Mode Configuration Options

Bit Name Function

15:11 Reserved Read returns zero.

10 MINT Minimal Transparency

0 = Generate two-byte transparency sequences. This option will use codes

<T5> through <RM><T20> (if possible) for received data containing two back-to-

back bytes requiring transparency (Rev C and later).

1 = Generate one-byte transparency sequences. This option will only use codes

<T1> through <T4> for received data (Rev B and later).

9 SERM Special Error Reporting Mode

0 = Ignore unrecognized in-band commands.

1 = Generate <0x45> (“E” for error) in response to any unrecognized in-band

commands.

8FSMSFramed Sub-Mode Startup

0 = Upon successful connection, enter Transparent Sub-Mode. An <FLAG>

is required to enter Framed Sub-Mode.

1 = Upon successful connection, immediately enter Framed Sub-Mode. The first

received <err> (from a successful hunt) is transformed into an <flag>.

7:0 XMTT Transmitter Threshold

This value represents the number of bytes before a transmission is started. The follow-

ing values are special:

0 The same as ten. Upon receipt of ten bytes, data is transferred. The DTE must

supply a closing flag within the required time or an underrun will occur.

255 The same as infinity, e.g. never start a packet until the closing flag is received.

UAA V.29 MODE

Bit Name Function

15:3 Reserved Read returns zero.

2 RUDE 0 = Disables rude disconnect.

1 = Enables rude disconnect.

1V29ENA0 – Disables V.29.

1 – Enables V.29.

0 Reserved Read returns zero.