UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 66

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

26
(a) Port mode
(b) Control signal input/output mode
(i)
(ii)
(i)
(ii)
(iii) WR (Write Strobe)
(iv) WAIT (Wait)
(v)
(vi) HLDRQ (Hold Request)
(vii) HLDAK (Hold Acknowledge)
With PD784026
Each port not set in the control mode can be set in the input or output mode in 1-bit units by using the port 6 mode
register (PM6).
With PD784021
Of the port not set in the control mode, P60 through P63 function as output port pins, and P64 through P67 can
be set in the input or output mode in 1-bit units by using the port 6 mode register (PM6).
A16 to A19 (Address Bus)
Upper address bus output pins in case of external memory space extension (10000H to FFFFFH).
These pins operate in accordance with the memory extension mode register (MM).
RD (Read Strobe)
Pin that outputs the strobe signal for an external memory read operation.
Operates in accordance with the memory extension mode register (MM).
In the PD784021, this pin always operates as the RD pin.
Pin that outputs the strobe signal for an external memory write operation.
Operates in accordance with the memory extension mode register (MM).
In the PD784021, this pin always operates as the WR pin.
Wait signal input pin. Operates in accordance with the programmable wait control registers (PWC1, PWC2).
REFRQ (Refresh Request)
This pin outputs refresh pulses to pseudo-static memory when this memory is connected
externally. Operates in accordance with the refresh mode register (RFM).
External bus hold request signal input pin. Operates in accordance with the hold mode register
(HLDM).
Bus hold acknowledge signal output pin. Operates in accordance with the hold mode register
(HLDM).
CHAPTER 2 PIN FUNCTIONS