Obsidian-Knowledge-Base/X-Knowledge-Base/wiki/Note 14 Ethernet.md

---

tags: [entity] type: entity topic: stm32-lower note: 14 created: 2026-07-16

updated: 2026-07-16

Note 14: Ethernet (lower/stm32/05~09)

Projects

#	Directory	Description
05	05_ethernet_test_register	Ethernet basic init & test (W5500)
06	06_ethernet_tcp_server_register	TCP Server
07	06_ethernet_tcp_client_register	TCP Client
08	08_ethernet_udp_register	UDP communication
09	09_ethernet_webserver_register	Web Server (HTTP)

Code Accuracy Audit

Path Audit

Claimed Path	Actual Path	Status
stm32/stm32/05_ethernet_test_register/...	05_ethernet_test_register/...	WRONG — double stm32/ prefix
.../Hardware/SPI/spi.h	05_ethernet_test_register/Hardware/SPI/spi.h	✅ Correct (minus double stm32)
.../Interface/Ethernet/eth.c	05_ethernet_test_register/Interface/Ethernet/eth.c	✅ Correct
.../User/main.c	05_ethernet_test_register/User/main.c	✅ Correct
stm32/06_ethernet_tcp_server_register/App/TCP/tcp.c	06_ethernet_tcp_server_register/App/TCP/tcp.c	✅ Correct
stm32/09_ethernet_webserver_register/App/Web/web_server.c	Exists at 09_ethernet_webserver_register/App/Web/	✅ Correct

SPI Code (spi.c)

Claimed by Note	Actual Code	Match?
`RCC->APB2ENR	= RCC_APB2ENR_IOPBEN`	Line 14
`RCC->APB2ENR	= RCC_APB2ENR_IOPDEN`	Line 15
`RCC->APB1ENR	= RCC_APB1ENR_SPI2EN`	Line 16
CS — PD3: GPIO push-pull	Lines 20-21	✅ Match
SCK — PB13: AF push-pull	Lines 24-26	✅ Match
MOSI — PB15: AF push-pull	Lines 29-31	✅ Match
MISO — PB14: floating input	Lines 34-36	✅ Match
`SPI2->CR1	= SPI_CR1_MSTR`	Line 41
`SPI2->CR1	= SPI_CR1_SSM; SPI2->CR1	= SPI_CR1_SSI`
`SPI2->CR1 &= ~(SPI_CR1_CPOL	SPI_CR1_CPHA)` (Mode 0)	Line 48
SPI2->CR1 &= ~SPI_CR1_BR (div 2)	Line 51	✅ Match
SPI2->CR1 &= ~SPI_CR1_DFF (8-bit)	Line 56	✅ Match
SPI2->CR1 &= ~SPI_CR1_LSBFIRST (MSB first)	Line 59	✅ Match
`SPI2->CR1	= SPI_CR1_SPE`	Line 62
CS_LOW / CS_HIGH (via GPIOD->ODR)	Lines 68, 72	✅ Match
while ((SPI2->SR & SPI_SR_TXE) == 0) {}	Line 80	✅ Match
SPI2->DR = byte	Line 84	✅ Match
while ((SPI2->SR & SPI_SR_RXNE) == 0) {}	Line 88	✅ Match
return (uint8_t)(SPI2->DR & 0xff)	Line 92	✅ Match

W5500 ETH Code (eth.c)

Claimed by Note	Actual Code	Match?
Global arrays: ip = {192,168,44,222}, mac = {110,120,130,140,150,160}, submask = {255,255,255,0}, gateway = {192,168,44,1}	Lines 12-15	✅ Match
SPI_Init() called first	Line 28	✅ Match
user_register_function() called	Line 31	✅ Match
RST on PG7: `RCC->APB2ENR	= RCC_APB2ENR_IOPGEN`	Line 48
`GPIOG->CRL	= GPIO_CRL_MODE7; GPIOG->CRL &= ~GPIO_CRL_CNF7`	Lines 51-52
GPIOG->ODR &= ~GPIO_ODR_ODR7 (RST low)	Line 55	✅ Match
Delay_us(800)	Line 57	✅ Match
`GPIOG->ODR	= GPIO_ODR_ODR7` (RST high)	Line 59
setSHAR(mac), setSIPR(ip), setSUBR(submask), setGAR(gateway)	Lines 68, 78, 80, 82	✅ Match

Ethernet main.c (05_ethernet_test_register)

Note does not detail main.c content. Actual code shows:

• Calls USART_Init(), prints banner, calls ETH_Init(), then infinite loop (27 lines)
• No SPI or W5500 API calls in main — all init happens inside ETH_Init()

TCP Server (06_ethernet_tcp_server_register)

Note's state machine description is accurate:

• SOCK_CLOSED → socket(SN, Sn_MR_TCP, 8080, SF_TCP_NODELAY)
• SOCK_INIT → listen(SN)
• SOCK_ESTABLISHED → handle Sn_IR_CON, get client IP/port
• SOCK_CLOSE_WAIT → close(SN)

Functions TCP_RecvData and TCP_SendData match actual code.

Web Server (09_ethernet_webserver_register)

Note's description of web_server.c with content[] HTML string, parse_url_action, and do_led_action matches actual code.

Summary

Overall Accuracy: Very High (95%+)

Issues Found:

1. Double stm32/stm32/ path for project 05
2. Delay_us(800) is accurate (comment says 500us but actual code uses 800us delay)
3. All register-level SPI/W5500 code matches perfectly