Z8E520 Datasheet, PDF (23/43 Pages) Zilog, Inc. – 1.5 MBPS USB Device Controller

Zilog
Z8E520/C520
1.5 MBPS USB Device Controller
COMMUNICATION REGISTER DEFINITIONS (USB MODE)
The following definitions on pages 23–26 describe in detail available 7.5 K ohm pull-up internal to the chip. An external
the specific USB mode registers as illustrated in Figure 15. 7.5 K ohm pull-up should be provided for DATA.
1
PORT A, PORT B: I/O Port data registers. At all times, a
read to this port should indicate the current state at the
pins. Read/Write.
ADDR: Determines the USB Device Address. Cleared by
USB or POR Reset. Read/Write.
SIE MODE: Determines the mode of the SIE communica-
tion pins (Port B7:6). Read/Write. The SIE modes are as
follows:
SIE Mode Description
Port B7 Port B6
RS232: Port B7 is serial data out (T x D). Port B6 is serial
data in (R x D). These signals are CMOS-level signals,
positive logic. Appropriate transceiver circuitry must be
added externally to comply with RS232-C signal levels at
the device connector.
SIE POWER: Powers up the SIE when USB Resume sig-
naling has been received, or shuts down SIE in prepara-
tion for USB Suspend. Read/Write.
FORCE RESUME: Forces a K state on the USB pins.
Read/Write.
00000000
00000001
00000010
00000100
Other
GPIO
USB
PS/2
RS232-C 1200 Baud
N81 Full Duplex
Reserved
I/O
I/O
D+
D–
CLOCK DATA
DATA IN DATA OUT
Reserved Reserved
GPIO: The SIE is off and the communication lines are
standard I/O pins on Port B.
ACTIVITY: This bit is set by the SIE when the state of the
USB pins changes. Read/Write.
J STATE: This bit is set when the USB is in the ‘J’ state
and cleared when in ‘K’ or ‘SE0’. Read only.
EP MODE: These bits define the operation of the non-zero
endpoints of the SIE. Changing this mode resets the SIE,
while writing the same value does not. Read/Write. The
EP modes are as follows:
USB: Port B7 is D+, which connects to pin 3 on a series A,
or series B USB connector and whose conductor is green.
Port B6 is D–, which connects to pin 2 on a series A or se-
ries B USB connector and whose conductor is white. An
external 7.5K pull-up should be provided for D–.
PS/2: Port B7 is CLOCK, which connects to pin 5 on a
male 6-pin Mini-DIN connector and Port B6 is DATA, which
connects to pin 1 on a male 6-pin Mini-DIN connector.
These signals are open-drain. The CLOCK pin has an
EP Mode
000
001
010
011
100
101
110
111
Description
EP1 OFF, EP2 OFF
EP1 IN, EP2 OFF
EP1 OUT, EP2 OFF
EP1 CONTROL
EP1 OUT, EP2 OUT
EP1 IN, EP1 OUT
EP1 OUT, EP1 IN
EP1 IN EP2 IN
DS97KEY2005
PRELIMINARY
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