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2Msc Keyboard Scan Expansion/GPIO Expansion device
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4
5What is smsc-ece1099?
6----------------------
7
8The ECE1099 is a 40-Pin 3.3V Keyboard Scan Expansion
9or GPIO Expansion device. The device supports a keyboard
10scan matrix of 23x8. The device is connected to a Master
11via the SMSC BC-Link interface or via the SMBus.
12Keypad scan Input(KSI) and Keypad Scan Output(KSO) signals
13are multiplexed with GPIOs.
14
15Interrupt generation
16--------------------
17
18Interrupts can be generated by an edge detection on a GPIO
19pin or an edge detection on one of the bus interface pins.
20Interrupts can also be detected on the keyboard scan interface.
21The bus interrupt pin (BC_INT# or SMBUS_INT#) is asserted if
22any bit in one of the Interrupt Status registers is 1 and
23the corresponding Interrupt Mask bit is also 1.
24
25In order for software to determine which device is the source
26of an interrupt, it should first read the Group Interrupt Status Register
27to determine which Status register group is a source for the interrupt.
28Software should read both the Status register and the associated Mask register,
29then AND the two values together. Bits that are 1 in the result of the AND
30are active interrupts. Software clears an interrupt by writing a 1 to the
31corresponding bit in the Status register.
32
33Communication Protocol
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35
36- SMbus slave Interface
37	The host processor communicates with the ECE1099 device
38	through a series of read/write registers via the SMBus
39	interface. SMBus is a serial communication protocol between
40	a computer host and its peripheral devices. The SMBus data
41	rate is 10KHz minimum to 400 KHz maximum
42
43- Slave Bus Interface
44	The ECE1099 device SMBus implementation is a subset of the
45	SMBus interface to the host. The device is a slave-only SMBus device.
46	The implementation in the device is a subset of SMBus since it
47	only supports four protocols.
48
49	The Write Byte, Read Byte, Send Byte, and Receive Byte protocols are the
50	only valid SMBus protocols for the device.
51
52- BC-LinkTM Interface
53	The BC-Link is a proprietary bus that allows communication
54	between a Master device and a Companion device. The Master
55	device uses this serial bus to read and write registers
56	located on the Companion device. The bus comprises three signals,
57	BC_CLK, BC_DAT and BC_INT#. The Master device always provides the
58	clock, BC_CLK, and the Companion device is the source for an
59	independent asynchronous interrupt signal, BC_INT#. The ECE1099
60	supports BC-Link speeds up to 24MHz.
61