Low Level:

 

[DESIGN NOTES]

INPUT FROM THE NINTENDO CONTROLLER:
The microcontroller must put out a high pulse on the Pulse pin, once this
pulse goes low, A is asserted. All buttons are down if the signal in the
data pin is low during their read pulse. Next the pulse line pulses 7 times
with the first pulse correlating to B, the second to Select, and so on as
shown below:

Read #| 1.2......3......... 4.....5......6.......7.......8
--------+--------------------------------------------------
Button | A B SELECT START UP DOWN LEFT RIGHT
WAVEFORM OF CONTROLLER

Nintendo Controller Pin Out: 
                          +---+
                 GND ---> | o  \
                 LATCH -> | o o + <-- +5Vdc
                 CLOCK -> | o o | <-- N/C
                 DATA --> | o o | <-- N/C
                          +-----+
THE LCD:

We're using the Hyundai HG25504NG-01 with an SED1330F controller.
Pin Out:

               PIN| VAR | Description
                --------------------------------
                 1 FG    GND
                 2 VSS   GND
                 3 VDD   +5V
                 4 V0    Variable (low is higher contrast)
                 5 /RES  Reset
                 6 /RD   Read
                 7 /WR   Write
                 8 /CS   Chip Select
                 9 A0    Data Type Select
                 10 DB0  Data Display Bit 0
                 11 DB1  Data Display Bit 1
                 12 DB2  Data Display Bit 2
                 13 DB2  Data Display Bit 3
                 14 DB2  Data Display Bit 4
                 15 DB2  Data Display Bit 5
                 16 DB2  Data Display Bit 6
                 17 DB2  Data Display Bit 7

Initialize Sequence:

Bit:                [7 6 5 4 3 2 1 0 ]
                 -------------------------------
                 C  [0  1 0  0  0  0  0  0 ]
                 P1 [0  1 IV 1 W/S M2 M1 M0]
                 P2 [WF 0 0  0 |<---FX--->|]
                 P3 [0  0 0  0 |<---FY--->|]
                 P4 [|<-------C/R-------->|]
                 P5 [|<-------TC/R------->|]
                 P6 [|<-------L/F-------->|]
                 P7 [|<-------APL-------->|]
                 P8 [|<-------APH-------->|]


The LCD contrast voltage actually changes depending on what mode the LCD is in (the LCD has 3 modes: Text, Graphics, and Text and Graphics). We used the Text and Graphics mode, requiring a contrast (V0) voltage of ~-11.25 V. Originally we thought that this could pose a problem because the max voltage on V0 is such that Vcc - V0 = +15V, or that V0 can range to -20V. Fortunately this voltage was easily obtained using the ECE 232 Protoboard setup.