8x16 snake

Compiling the code

Install VSCode
Install the PlatformIO extension
Navigate to the PlatformIO > Quick Access > PIO Home > Devices
In the Platforms > Embedded search for "Intel".
Find the "Intel MCS-51 (8051)" entry and click on it.
In the "Intel MCS-51 (8051) page click Install, this project used version 2.1.0

Uploading the code

Connect to the MCU serial port (verified CP2102 and CH341A)
MCU Gnd pin 20 - Serial Gnd
MCU RX pin 21 - Serial Tx
MCU Tx pin 22 - Serial RX
Open platformio.ini, find the "upload_port" line and change it to match the serial device that is connected to the microcontroller.
PlatformIO > STC15F2K60S2 > General > Build or Upload

Description

8x16 game based on STC15F2K60S2 - an Intel 8051 clone by STC.

The purpose of this project is to:

Rewrite the stock firmware with some alternative games.
Teach microcontroller programming on a cheap and starightforward platform

Microcontroller details: STC15F2K60S2 28I-PDIP40 1845HVV065.XD

Microcontroller decoding:

Field	Details
STC	The program Flash in user program area can not be used as EEPROM, but there are special EEPROM
15	15 STC 1T 8051 MCU, Speed is 8~12 times faster than the traditional 8051 in the same working frequency. STC15 series MCU with super high-speed CPU core of STC-Y5 works 20% faster than STC early 1T series such as STC12/STC11/STC10 series at same clock frequency.
F	Operating Voltage 5.5V~4.2V
2K	Large capacity of on-chip 2048 bytes SRAM: 256 byte scratch-pad RAM and 1792 bytes of auxiliary RAM
60	Program space, e.g. 60:60KB
S2	2 UARTs (can be used simultaneously)' SPI' Internal EEPROM' A/D Converter(PWM also can be used as DAC)' CCP/PWM/PCA
28	Up to 28MHz
I	Industrial, -40c-85c
PDIP 40	Package

The MCU, according to "Chapter 3 Memory Organization and SFRs" has a total of 2048 bytes SRAM of RAM

256 byte scratch-pad RAM (idata)
1792 bytes of auxiliary RAM (XRAM, xdata)

Storage IAP can be used to store program data. Program memory: 0000H~0EFFFH (60K)

Hardware required

8x16 game

USB Serial converters tested:

Silicon Labs CP2102
CH341A based programmer that is switched to USB to Serial converter mode (Jumper between pins 2 and 3)

Alternative environment setup

The recommended compiler for this project is sdcc, alternatively Keil uVision can be used to compile code for Intel 8051. Keil was originally used for this project, but the project has not switched to sdcc.

Official STC documentation recommends Keil uVision. The development environment will have to be

Install Keil uVision C51, the version for 8051 microcontrollers. The version used in this project is V5.27.1.0. It will include the C compiler - C51 and the Intel 8051 assembly compiler A51.
Download "STC ISP programming software (v6.86)" from http://www.stcmicro.com/rjxz.html
Open "Keil ICE Settings" tab, Add MCU type to Keil

Hardware tweaks

Capacitors at the MCU power ports. The spec asks for a 47uF electrolytic and a 0.1uF ceramic capacitor at the power input of the MCU, need to add those.
Reroute OK and Reset buttons to empty pins to free up UART0 for programming and debug output.

Uart

Two high-speed asynchronous serial ports UARTs (UART1/UART2 can be used simultaneously and regarded as 5 serial ports by shifting among 5 groups of pins):

UART1(RxD/P3.0, TxD/P3.1) can be switched to (RxD_2/P3.6, TxD_2/P3.7), also can be switched to (RxD_3/P1.6, TxD_3/P1.7);
UART2(RxD2/P1.0, TxD2/P1.1) can be switched to (RxD2_2/P4.6, TxD2_2/P4.7).

STC15F2K60S2 pinout

MCU Board logical layout

Connection	GPIO Pin	GPIO Pin	Connection
R4+	P00	P45	R1+
R6+	P01	P27	R3+
R7+	P02	P26	C1-
R5+	P03	P25	D1-
R2+	P04	P24	C0-
R8+	P05	P23	D0-
R11+	P06	P22	C5-
R9+	P07	P21	C3-
	P10	P20	R0+
R14+	P11	P44	C2-
R13+	P12	P42	C4-
R10+	P13	P41	D2-
R12+	P14	P37	BtnLeft
	P15	P36	BtnDown
	P16	P35	C6-
C7-	P17	P34
R15+	P54	P33	BtnRight
5v	VCC	P32	BtnUp
Spkr	P55	P31	BtnRst / U0 TX
0v	GND	P30	BtnOK / U0 RX


 Rx - Row number x in the dot matrix display, X in [0, 15]. Rows are positive
 Cy - Column number y in the dot matrix display, Y in [0, 7]. Clumns are negative
 Dz - Digit number z, z in [0, 2]. Digit "rows" are negative, thank you.

Each digit has the following layout corresponding to the dot matrix columns:
              Col 6+
     Col 5+              Col 0+
              Col 4+
     Col 2+              Col 3+
              Col 1+

Board Physical layout MCU

Connection	MCU Pin	MCU Pin	Connection
A16+	1	40	A3+
A15+	2	39	A5+
A12+	3	38	A14- / B14- / C8+
A10+	4	37	C3-
A9+	5	36	A4- / B4- / C2+
B8+	6	35	C1-
B5+	7	34	A6- / B6- / C10+
B3+	8	33	A7- / B7- / C9+
	9	32	A8+
B15+	10	31	A13- / B13- / C7+
B10+	11	30	A11- / B11- / C6+
B9+	12	29	C5-
B16+	13	28	BtlLeft
	14	27	BtnDown
	15	26	A2- / B2- / C4+
A1/B1-	16	25
B12+	17	24	BtnRight
5V	18	23	BtnUp
SPKR	19	22	BtnReset
Gnd	20	21	BtnOk