ISP1130DL Philips Semiconductors, ISP1130DL Datasheet - Page 44

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

Philips Semiconductors
9397 750 06895
Objective specification
10.10 Keyboard matrix implementation
10.8 I/O description
10.9 I/O port mapping
The following groups of I/O lines are available for interfacing a keyboard matrix to the
ISP1130:
MX0 to MX7 — return lines for keyboard matrix; inputs with internal 8.2 k pull-up
resistors, 5 V tolerant. Inputs MX3 and MX4 are multiplexed with the SCL and SDA
lines respectively. This allows the ISP1130 firmware to read configuration data from
an external EEPROM via SDA and SCL, e.g. upon a hardware or a USB bus reset.
MY0 to MY17 — scan lines for keyboard matrix; bidirectional lines with internal 82 k
pull-down resistors and 8.2 k pull-up resistors. The pull-down resistors are selected
by setting bit DisableKBDMatrix in the USBCON register. In Idle mode these lines are
inputs, which are OR-ed together to generate an interrupt when a key is pressed.
CAPSLOCK / NUMLOCK / SCRLOCK — open drain outputs for driving Caps Lock,
Num Lock and Scroll Lock indicator LEDs (max. 8 mA).
Remark: When accessing external functions or devices via the ISP1130 bus lines, it
is recommended to isolate the MYn lines by means of analog switches, controlled via
output MEMSEL/UPGL. This prevents bus conflicts during keyboard scanning.
Table 74
their use in ISP1130.
Table 74: Mapping of I/O ports between ISP1130 and 80C51
The ISP1130 can support a maximum key matrix size of 18
typical implementation of the keyboard matrix is shown in
ISP1130 ports
MY0 to MY7
MY8 to MY15
MY16
MY17
MEMSEL/UPGL
CAPSLOCK
NUMLOCK
SCRLOCK
n.c.
n.c.
MX0 to MX7
provides the mapping of standard 80C51 input/output ports with respect to
Rev. 01 — 23 March 2000
80C51 ports
P0.0 to P0.7
P2.0 to P2.7
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
P3.0 to P3.7
USB compound hub with keyboard controller
Description
keyboard scan lines
keyboard scan lines
keyboard scan lines
keyboard scan lines
chip select output for an external EEPROM;
upstream port GoodLink indicator output
control output for Caps Lock LED indicator
control output for Num Lock LED indicator
control output for Scroll Lock LED indicator
not used
not used
keyboard return lines
Figure
© Philips Electronics N.V. 2000. All rights reserved.
8, totalling 144 keys. A
7.
ISP1130
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