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@ -148,7 +148,9 @@ Although Arduino IDE does not [seem](https://github.com/arduino/Arduino/issues/4
## Memory constraints ## Memory constraints
If you are going to use large/combined panels make sure to check for [memory constraints](/doc/i2s_memcalc.md). If you are going to use large/combined panels make sure to check for [memory constraints](/doc/i2s_memcalc.md).
NOTE: You *cannot* use PSRAM to expand the amount of memory available to use by this library. ESP32 hardware [only allows DMA transfer from *internal* SRAM](https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-I2S-DMA/issues/55), so you will be limited to the 200KB or so of usable SRAM of the ESP32 regardless of how many megabytes of PSRAM you may have connected. NOTE: You can use PSRAM to expand the amount of memory available only on the ESP32-S3 and with Octal SPI-RAM (ESP32 S3 N8R8 variant). However, due to bandwidth limitations, the maximum output frequency is 10Mhz, which will limit the real world number of panels that can be chained without the refresh rate being impacted.
For all other ESP32 variants (like the most popular ‘original’ ESP32), the hardware [only allows DMA transfer from *internal* SRAM](https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-I2S-DMA/issues/55), so you will be limited to the 200KB or so of usable SRAM of the ESP32 regardless of how many megabytes of PSRAM you may have connected.
## Can I use with a larger panel (i.e. 64x64px square panel)? ## Can I use with a larger panel (i.e. 64x64px square panel)?
If you want to use with a 64x64 pixel panel (typically a HUB75*E* panel) you MUST configure a valid *E_PIN* to your ESP32 and connect it to the E pin of the HUB75 panel! Hence the 'E' in 'HUB75E' If you want to use with a 64x64 pixel panel (typically a HUB75*E* panel) you MUST configure a valid *E_PIN* to your ESP32 and connect it to the E pin of the HUB75 panel! Hence the 'E' in 'HUB75E'