Silicon Laboratories SI2493/57/34/15/04 manual Minimal Transparency, Special Error Reporting Mode

AN93

5.7.21.U87 (Synchronous Access Mode Configuration Register)

U87 SAM Synchronous Access Mode Configuration Options

Bit	Name		Function
15:11	Reserved	Read returns zero.
10	MINT	Minimal Transparency
		Host software must always set this bit.
		0	= Generate two-byte <EM> transparency sequences. This option will use codes
		<EM><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 <EM>transparency sequences. This option will only use codes
		<EM><T1> through <EM><T4> for received data (Rev B and later).
9	SERM	Special Error Reporting Mode
		0	= Ignore unrecognized in-band commands.
		1	= Generate <EM><0x45> (“E” for error) in response to any unrecognized in-band
		commands.
8	FSMS	Framed Sub-Mode Startup
		0	= Upon successful connection, enter Transparent Sub-Mode. An <EM><FLAG>
		is required to enter Framed Sub-Mode.
		1	= Upon successful connection, immediately enter Framed Sub-Mode. The first
		received <EM><err> (from a successful hunt) is transformed into an <EM><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 are 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.

120 Rev. 1.3