====== Display driver module ====== 32 SPI-driven displays ===== Schematic ===== The concept is to buffer the time-critical clock signal. A wire connected directly to the MCU is loaded by the long distance (resistance in the connectors and wires) and could be susceptible to noise. Using a 541 buffer and shunt resistors controls this impedance. The serial data and data/command (DC) signals are also buffered to avoid time propagation errors. The second purpose is to use a chain of shift registers to provide chip select (CS) signals. It is functionally equivalent to a DOUT module, but the header is directly compatible with GPIO on the Core. The pinout for the display connectors is as follows: {{:dispdriver:header_j1-j2.png?direct&600|}}\\ (Power is connected to pin 10.) ---- ===== BOM v1.0 ===== ^Type ^Part ^Value ^Device^ | Caps | C1 | 100n | C025-025X050 | | | C2 | 100n | C025-025X050 | | | C3 | 100n | C025-025X050 | | | C4 | 100n | C025-025X050 | | | C5 | 100n | C025-025X050 | | | C6 | 100n | C025-025X050 | | | C7 | 100n | C025-025X050 | | ICs | IC1 | 74HC541N | 74HC541N | | | IC2 | 74HC541N | 74HC541N | | | IC3 | 74HC541N | 74HC541N | | | IC4 | 74HC595N | 74HC595N | | | IC5 | 74HC595N | 74HC595N | | | IC6 | 74HC595N | 74HC595N | | | IC7 | 74HC595N | 74HC595N | | Headers | J1 | PINHD-2X54WALL | PAK100/2500-10 | | | J2 | PINHD-2X54WALL | PAK100/2500-10 | | | J3 | PINHD-2X54WALL | PAK100/2500-10 | | | J4 | PINHD-2X54WALL | PAK100/2500-10 | | | J5 | PINHD-2X54WALL | PAK100/2500-10 | | | J6 | PINHD-2X54WALL | PAK100/2500-10 | | | J7 | PINHD-2X54WALL | PAK100/2500-10 | | | J8 | PINHD-2X54WALL | PAK100/2500-10 | | | J9 | +5V | 22-23-2031 | | | J10B | PINHD-2X54WALL | PAK100/2500-10 | | | J10B1 | PINHD-2X54WALL | PAK100/2500-10 | | | J15A | PINHD-2X8THTTHT | PAK100/2500-16 | | | J15A1 | PINHD-2X8THTTHT | PAK100/2500-16 | | Resistors | R1 | ~220R | 0207/10 | | | R2 | ~220R | 0207/10 | | | R3 | ~220R | 0207/10 | | | R4 | ~220R | 0207/10 | | | R5 | ~220R | 0207/10 | | | R6 | ~220R | 0207/10 | | | R7 | ~220R | 0207/10 | | | R8 | ~220R | 0207/10 | | | R9 | ~220R | 0207/10 | | | R10 | ~220R | 0207/10 | | | R11 | ~220R | 0207/10 | | | R12 | ~220R | 0207/10 | | | R13 | ~220R | 0207/10 | | | R14 | ~220R | 0207/10 | | | R15 | ~220R | 0207/10 | | | R16 | ~220R | 0207/10 | | | R17 | ~220R | 0207/10 | | | R18 | ~220R | 0207/10 | | | R19 | ~220R | 0207/10 | | | R20 | ~220R | 0207/10 | | | R21 | ~220R | 0207/10 | | | R22 | ~220R | 0207/10 | | | R23 | ~220R | 0207/10 | | | R24 | ~220R | 0207/10 | | | R25 | ~1k | 0207/10 | | | R26 | ~1k | 0207/10 | | | R27 | ~1k | 0207/10 | | | R28 | ~1k | 0207/10 | | | R29 | ~1k | 0207/10 | | | R30 | ~1k | 0207/10 | | | R31 | ~1k | 0207/10 | | | R32 | ~1k | 0207/10 | | | R33 | ~1k | 0207/10 | | | R34 | ~1k | 0207/10 | | | R35 | ~1k | 0207/10 | | | R36 | ~1k | 0207/10 | | | R37 | ~1k | 0207/10 | | | R38 | ~1k | 0207/10 | | | R39 | ~1k | 0207/10 | | | R40 | ~1k | 0207/10 | | | R41 | ~1k | 0207/10 | | | R42 | ~1k | 0207/10 | | | R43 | ~1k | 0207/10 | | | R44 | ~1k | 0207/10 | | | R45 | ~1k | 0207/10 | | | R46 | ~1k | 0207/10 | | | R47 | ~1k | 0207/10 | | | R48 | ~1k | 0207/10 | | | R49 | ~1k | 0207/10 | | | R50 | ~1k | 0207/10 | | | R51 | ~1k | 0207/10 | | | R52 | ~1k | 0207/10 | | | R53 | ~1k | 0207/10 | | | R54 | ~1k | 0207/10 | | | R55 | ~1k | 0207/10 | | | R56 | ~1k | 0207/10 | ===== Versions ===== v1.0: first release. Erratum: there is a significant error in that J15 is __mirrored__. The simplest way to get it working is to swap pairs of the ribbon wires as shown: {{::dispdriver:mirrored_j15.jpg?direct&400|}} Here the header notches are aligned with the silkscreen. Only the first six wires are required. ===== Assembly ===== All parts are THT, start with resistors and caps, IC sockets then headers. ---- ==== Interconnection to Core ==== J10B connects to J10B. J15A to J15A. Note the mirrored connection on v1.0 J15A1/J10B1 chain another Display Driver. Note that the J15 connection should not be mirrored for subsequent boards. J9 is a power supply input that is sent to the displays over headers J1-J8. It may be better to wire the displays directly to the power supply rather than using the ribbon cable and connectors. ==== Dimensions ==== The PCB is 100*100mm with 3.2mm diameter holes centred 3.5mm from the edges. ---- ==== License ==== Currently the design is (c) 2018 antilog devices with all rights reserved; all documentation is CC BY-NC-SA 3.0.