Micromodem memory map:

ISTRB:
	/IS=0:

	0x0000		flash memory	(+A0,A1 in CLE,ALE)
	0x2000		external interface (enabled by EXTON in control reg)
	0x4000		uart A
	0x6000		uart B
	0x8000		control register (when writing)
	0xa000		unused
	0xc000		unused
	0xe000		unused
	

MSTRB:
	/DS=0:
	0x0000-0x7fff		eprom (8-bit wide)

	/PS=0:
	0x00000-0x07fff		static RAM page 0 (32 kwords)
	0x20000-0x27fff		static RAM page 1 
	0x40000-0x47fff		static RAM page 2
	0x60000-0x67fff		static RAM page 3
	0x80000-0x87fff		static RAM page 4
	0xa0000-0xa7fff		static RAM page 5
	0xc0000-0xc7fff		static RAM page 6
	0xe0000-0xe7fff		static RAM page 7

	Each page of the 256k x 16bit static RAM is 32 kwords.
	The high byte of the address is in the page extension register(?).
	Address lines 15 and 16 are ignored by the RAM, and 20-22 aren't
	even connected at the DSP.

Serial Peripheral Interface bus:
							select line
							in control reg:

	DS1306		Real Time Clock			(RTCSEL,   0x0200)
	AD8400		Programmable Gain Amplifier	(/PGASEL,  0x0400)
	LTC1098L	Sensor 8-bit ADC		(/SADCSEL, 0x8000)
	(various)	Timing Generator		(FSSEL,    0x0800)

	TLV5616		DAC
	ADS7822EC	ADC

	RTCSEL, /PGASEL, FSSEL, (EXTSEL1-3), and SADCSEL are in the
	control register. SDI, SDO, and SCLK are from buffered
	synchronous serial port 1.

	The DAC and ADC are on transmit and receive, respectively,
	are on buffered synchronous serial port 2, with the clock
	taken from the timing generator.