as part of the project fpdoom Port of the DOOM game for the button phones on the Spreadtrum SC6531 chip was prepared. The modifications of the SPREADTRUM SC6531 chip occupy about half of the market of cheap button phones of Russian brands (usually the rest on MediaTek MT6261). The chip is based on the ARM926EJ-S processor with a frequency of 208 MHz (SC6531E) or 312 MHz (SC6531DA), architecture of the ARMV5TeJ processor.
Porch complexity is due to the following factors:
- third -party applications on these phones are not provided.
- Small volume of RAM – only 4 megabytes (brands/sellers often indicate this as 32MB – but this is an introduction, as megabits, not megabytes are meant).
- closed documentation (you can only find a leakage of the early and inferior version), so much was mined by reverse engineering.
At the moment, the work of only a small part of the chip is investigated – USB, screen and keys, so you can play only on the phone connected to the USB -cable computer (resources for the game are transmitted from the computer), there is also no sound in the game. In the current form, the game is launched on 6 of 9 tested phones on the SC6531 chip. To transfer this chip into the boot mode, you need to know which key to hold when loading (for the F+ F256 model – this is the “*” key, for Digma Linx B241 – the “Center” key, for F+ Ezzy 4 – the “1” key, for Vertex M115 – “Up”, for Joy’s S21 and Vertex C323 – “0”).