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Rodeo

oled_ssd130x_bulk.h

Generated from the header

This page is rodeo-sdk/common/oled_ssd130x_bulk.h — its comments and declarations. To change it, change the header.

Drop-in replacement for daisy::SSD130xI2CTransport, which sends ONE 2-byte I2C transaction PER DISPLAY BYTE (libDaisy dev/oled_ssd130x.h). A 128x64 frame is 8 pages x 128 bytes, so a stock Update() is ~1024 blocking transactions — on the order of 100 ms at 400 kHz. That is fine for 08_oled_i2c, which does nothing else, but fatal for a synth: the same main loop pumps rodeo::RodeoAdc and MidiUartHandler, so every frame would freeze the knobs and delay note-on.

Two changes:

  1. SendData() pushes a whole page in ONE transaction: [0x40][page bytes]. ~4x fewer bus turnarounds -> ~23 ms/frame instead of ~100 ms.
  2. A yield hook, invoked after each page. SSD130xDriver::Update() calls SendData() once per page, so the hook gives the app 8 chances per frame to pump the ADC scan / MIDI. Worst-case main-loop stall drops from a whole frame to a single page (~3 ms).

The hook is namespace-level rather than a member because the transport instance is unreachable from the app: OledDisplay::driver_ is PRIVATE and SSD130xDriver::transport_ is protected. gnu++14 (no inline variables), hence the .cpp.

Usage — identical to the stock transport apart from the template argument:

using OledType
    = OledDisplay<SSD130xDriver<128, 64, rodeo::Ssd130xI2cBulkTransport>>;
rodeo::SetOledYield(PumpIo);

Ssd130xI2cBulkTransport

class Ssd130xI2cBulkTransport

Members

  • using Config = daisy::SSD130xI2CTransport::Config — Same shape as the stock transport’s, so app-side config code is unchanged.

Ssd130xI2cBulkTransport::Init

void Init(const Config &config);

Ssd130xI2cBulkTransport::SendCommand

void SendCommand(uint8_t cmd);

Ssd130xI2cBulkTransport::SendData

void SendData(uint8_t *buff, size_t size);

SetOledYield

void SetOledYield(void (*fn)());

Called after each page is pushed. Must not touch the display, and must not block (no USB logging) — it runs in the middle of a frame.

OledLinkOk

bool OledLinkOk();

False once a transfer has been NAKed or timed out — i.e. no display is answering. Lets an app say so over serial instead of drawing into the void.