ISP1130DL Philips Semiconductors, ISP1130DL Datasheet - Page 45

• Manufacturer Part Number: ISP1130DL
• Description: Universal Serial Bus compound hub with integrated keyboard controller
• Manufacturer: Philips Semiconductors

Philips Semiconductors
9397 750 06895
Objective specification
10.11.1 Suspend
10.11 Suspend and resume
The keyboard scanning algorithm is as follows:
This algorithm helps to reduce EMI and power consumption.
When there is no activity on the USB bus for more than 3 ms, the device generates
an interrupt to the microcontroller to enter ‘suspend’ state.
The microcontroller can respond to a ‘suspend’ interrupt in three ways, depending on
the value of bit SuspendClock in the USBCON register when servicing the interrupt:
width
1. When no key press is detected within a predefined time interval, the
2. Pressing any key will result in the HIGH level of an MXn line to be transferred to
3. Upon a keyboard interrupt the microcontroller exits Idle mode and resumes
Fig 7. Typical keyboard matrix implementation.
microcontroller switches the MYn scan lines to ‘input’ and enters Idle mode.
an MYn input. Such a HIGH level (4.45 V typ.) exceeds V
interrupt, since all MYn lines are OR-ed together.
standard keyboard matrix scanning to determine which key was pressed.
(USBCON register)
DisableKBDMatrix
Rev. 01 — 23 March 2000
internal circuit
ISP1130
internal circuit
V CC
V CC
8.2 k
USB compound hub with keyboard controller
8.2 k
82 k
MYn
MXn
MY10
MY11
MY12
MY13
MY14
MY15
MY16
MY17
MY0
MY1
MY2
MY3
MY4
MY5
MY6
MY7
MY8
MY9
MX0
MX1
MX2
MX3
MX4
MX5
MX6
MX7
© Philips Electronics N.V. 2000. All rights reserved.
IH
Keyboard matrix
and generates an
ISP1130
MGS801
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