Silicon Laboratories SI2494/39, SI2493/57/34/15/04 manual U63 Bit Map, U65 Bit Map

AN93

			Table 63. U62 Bit Map (Continued)
4	Reserved	Must be set to zero.
3	Reserved	Must be set to zero.
2	FOH	0	= Automatic calibration timer set to 426 ms.
		1	= Automatic calibration timer set to 106 ms.
1	DL	0	= Digital loopback beyond ISOcap interface.
		1	= Digital loopback across ISOcap interface only.
0	Reserved	Must be set to zero.

U63 (DAAC2) is a bit-mapped register with bits 3:0 reserved and should be modified through a read-modify-write operation.

Bits 15:8 (LCS) function as an 8-bit unsigned measure of off-hook loop current with a resolution of 1.1 mA/bit.

Bits 7:4 (ACT) set the ac termination the Si3010/Si3018 presents to Tip and Ring. The ac impedance setting is dictated by the certification requirements for the country in which the modem is used.

			Table 64. U63 Bit Map
Bit	Name		Function
15:8	LCS	Off-hook loop current (1.1 mA/bit).
7:4	ACT	AC Termination Select
		ACT AC Termination
		0000	Real 600 Ω
		0011	220 Ω + (820 Ω 120 nF) and 220 Ω + (820 Ω 115 nF)
		0100	370 Ω + (620 Ω 310 nF)
		1111	Global complex impedance
3:0	Reserved	Read returns 0011.

U65 (DAAC4) is a bit-mapped register with bits 3:0, 12:5, and 15 reserved. Bits 1:0 and 6:5 must not be changed. Bit 14 (PWMG) = 0 (default) provides 0 dB gain to AOUT. PWMG = 1 provides a 6 dB gain to AOUT.

Bit 13 (PDN) = 0 enables the device for normal operation. PDN = 1 completely powers down both the Si3018/10 and the Si24xx chips. The bit takes effect at the carriage return of the AT command setting this bit high. Once this bit is set, the modem must be reset via the RESET pin to become active. When reset, the modem reverts to the default settings.

Bit 4 (PDL) = 0 (default) enables the device for normal operation. PDL = 1 powers the Si3018/10 down. This is a test mode typically used for board-level debugging, not normal modem operation.

U65 resets to 0x00E0 with a power-on or manual reset.

Table 65. U65 Bit Map

Bit	Name	Function
15	Reserved	Read returns zero.

14PWMG PWM gain. 0 = No gain.

1 = 6 dB gain applied to AOUT.

13PDN Power Down. 0 = Normal.

1 = Power Down.

Rev. 1.3 107