Clocked Serial Interface (Csi); Keyboard Interface (Kiu); General-Purpose I/O - NEC VR4181 mPD30181 User Manual

1.3.12 Clocked serial interface (CSI)

The V 4181 provides a clocked serial interface (CSI) which has an option to be configured as general-purpose I/O
R
pins. This interface supports slave mode operation only. The clocked serial interface requires allocation of 4 signals;
SI, SO, SCK, and FRM. The clock source for this interface is input on the pin assigned to SCK.

1.3.13 Keyboard interface (KIU)

The V 4181 provides support for an 8 x 8 key matrix. This keyboard interface can only be supported when the
R
CompactFlash interface is disabled and reconfigured to provide the SCANIN(7:0) inputs and the SCANOUT(7:0)
outputs.

1.3.14 General-purpose I/O

The V 4181 provides total 32 bits of general-purpose I/O. Sixteen of these, GPIO(31:16), are available through
R
pins allocated to other functions as shown in the following table. The DCD1#/GPIO29 is the only one of the 16 pins
that can cause the system's waking up from a low power mode if enabled by software. The other pins have no
functions other than those listed below.
The remaining 16 bits of general-purpose I/O, GPIO(15:0), are allocated to pins by default. Each of these pins can
be configured to support a particular interface such as CSI, secondary serial interface (RS-232-C), programmable
chip selects, or color LCD control. Otherwise, each of these pins can be also defined as one of the following:
• General-purpose input
• General-purpose output
• Interrupt request input
• Wake-up input
Pin designation
GPIO0 SI
GPIO1 SO
GPIO2 SCK
GPIO3 PCS0#
−
GPIO4
GPIO5 DCD2#
GPIO6 RTS2#
GPIO7 DTR2#
GPIO8 DSR2#
GPIO9 CTS2#
GPIO10 FRM/SYSCLK
GPIO11 PCS1#
GPIO12 FPD4
GPIO13 FPD5
GPIO14 FPD6/CD1#
GPIO15 FPD7/CD2#
Note This signal supports input only.
CHAPTER 1 INTRODUCTION
Table 1-3. GPIO(31:0) Pin Functions
Alternate function
User's Manual U14272EJ3V0UM
Pin designation
GPIO16 IORD#
GPIO17 IOWR#
GPIO18 IORDY
GPIO19 IOCS16#
Note
GPIO20
M/UBE#
GPIO21 RESET#
GPIO22 ROMCS0#
GPIO23 ROMCS1#
GPIO24 ROMCS2#
GPIO25 RxD1
GPIO26 TxD1
GPIO27 RTS1#
GPIO28 CTS1#
GPIO29 DCD1#
GPIO30 DTR1#
GPIO31 DSR1#
Alternate function
33