Silicon Laboratories SI2493/57/34/15/04, SI2494/39 manual U53 Bit Map, U54 Bit Map, U62 Bit Map

AN93

5.7.14. U53 (Modem Control Register 2)

U53 (MOD2) is a bit-mapped register with all bits, except bit 15, reserved (see Table 61). The AT&H11 command sets the V.23 1200/75 bps mode. Bit 15 (REV) is used to enable V.23 reversing. This bit is set to 0 (disable reversing) by default. Setting this bit to 1 enables reversing transmit and receive speeds. Reversing is initiated by the modem in the “origination mode” (low speed TX and high speed RX). U53 resets to 0x0000 with a power-on or manual reset.

5.7.15. U54 (Calibration Timing Register)

U54 (CALT) sets the time between off-hook and DAA calibration if timed calibration is enabled with the TCAL bit (U7D, bit 12). The OHCT bits (15:8) control this timing in 32 ms units.

5.7.16. U62–U66 (DAA Control Registers)

U62 (DAAC1) is a bit-mapped register with only bits 1, 2, and 8 available. All other bits in this register are reserved and must be set according to Table 63. U62 resets to 0x0804 with a power-on or manual reset.

Bit 1 (DL) = 1 or 0 causes digital loopback to occur beyond the isolation capacitor interface out to and including the analog hybrid circuit. Setting bit 1 high enables digital loopback across the isolation barrier only. This setting is used in conjunction with the AT&H and AT&T3 commands. DL must be set low for normal operation.

Bit 2 (FOH) controls when automatic Si3018/10 calibration takes place.

Table 61. U53 Bit Map

Bit Name Function

15REV V.23 Reversing. 0 = Disable.

1 = Enable.

14:0 Reserved Read returns zero.

		Table 62. U54 Bit Map
Bit	Name	Function
15:8	OHCT	Off-hook to calibration timing in 32 ms units. If enabled with TCAL (U7D bit 12), this value
		controls the time between off-hook and DAA calibration.
7:0	Reserved	Must be set to zero.

Table 63. U62 Bit Map

Bit	Name	Function
15:12	Reserved	Must be set to zero.
11	Reserved	Must be set to one.
10:9	Reserved	Must be set to zero.
8	OHS2	On-Hook Speed 2
		This bit, in combination with the OHS bit and the SQ[1:0] bits on-hook speeds specified
		are measured from the time the OH bit is cleared until loop current equals zero.
		OHS	OHS2	SQ[1:0]	Mean On-Hook Speed
		0	0	00	Less than 0.5 ms
		0	1	00	3 ms ±10% (meets ETSI standard)
		1	X	11	26 ms ±10% (meets Australia spark quenching spec)
		Note: The +GCI command does not modify OHS2, SQ[1:0].
7	Full 1	0 = Disable
		1 = Enable. +3.2 dBm maximum into 600 Ω (Si3018 only)
6:5	Reserved	Must be set to zero.

106 Rev. 1.3