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smsc_ece1099.txt

smsc_ece1099.txt 2.4 KB
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  1. What is smsc-ece1099?
    2. 

  2. ----------------------
    3. 

  3. 

  4. The ECE1099 is a 40-Pin 3.3V Keyboard Scan Expansion
    5. 

  5. or GPIO Expansion device. The device supports a keyboard
    6. 

  6. scan matrix of 23x8. The device is connected to a Master
    7. 

  7. via the SMSC BC-Link interface or via the SMBus.
    8. 

  8. Keypad scan Input(KSI) and Keypad Scan Output(KSO) signals
    9. 

  9. are multiplexed with GPIOs.
    10. 

  10. 

  11. Interrupt generation
    12. 

  12. --------------------
    13. 

  13. 

  14. Interrupts can be generated by an edge detection on a GPIO
    15. 

  15. pin or an edge detection on one of the bus interface pins.
    16. 

  16. Interrupts can also be detected on the keyboard scan interface.
    17. 

  17. The bus interrupt pin (BC_INT# or SMBUS_INT#) is asserted if
    18. 

  18. any bit in one of the Interrupt Status registers is 1 and
    19. 

  19. the corresponding Interrupt Mask bit is also 1.
    20. 

  20. 

  21. In order for software to determine which device is the source
    22. 

  22. of an interrupt, it should first read the Group Interrupt Status Register
    23. 

  23. to determine which Status register group is a source for the interrupt.
    24. 

  24. Software should read both the Status register and the associated Mask register,
    25. 

  25. then AND the two values together. Bits that are 1 in the result of the AND
    26. 

  26. are active interrupts. Software clears an interrupt by writing a 1 to the
    27. 

  27. corresponding bit in the Status register.
    28. 

  28. 

  29. Communication Protocol
    30. 

  30. ----------------------
    31. 

  31. 

  32. - SMbus slave Interface
    33. 

  33. 	The host processor communicates with the ECE1099 device
    34. 

  34. 	through a series of read/write registers via the SMBus
    35. 

  35. 	interface. SMBus is a serial communication protocol between
    36. 

  36. 	a computer host and its peripheral devices. The SMBus data
    37. 

  37. 	rate is 10KHz minimum to 400 KHz maximum
    38. 

  38. 

  39. - Slave Bus Interface
    40. 

  40. 	The ECE1099 device SMBus implementation is a subset of the
    41. 

  41. 	SMBus interface to the host. The device is a slave-only SMBus device.
    42. 

  42. 	The implementation in the device is a subset of SMBus since it
    43. 

  43. 	only supports four protocols.
    44. 

  44. 

  45. 	The Write Byte, Read Byte, Send Byte, and Receive Byte protocols are the
    46. 

  46. 	only valid SMBus protocols for the device.
    47. 

  47. 

  48. - BC-LinkTM Interface
    49. 

  49. 	The BC-Link is a proprietary bus that allows communication
    50. 

  50. 	between a Master device and a Companion device. The Master
    51. 

  51. 	device uses this serial bus to read and write registers
    52. 

  52. 	located on the Companion device. The bus comprises three signals,
    53. 

  53. 	BC_CLK, BC_DAT and BC_INT#. The Master device always provides the
    54. 

  54. 	clock, BC_CLK, and the Companion device is the source for an
    55. 

  55. 	independent asynchronous interrupt signal, BC_INT#. The ECE1099
    56. 

  56. 	supports BC-Link speeds up to 24MHz.
    57. 

  57.