Datasheet RP2040 (Raspberry Pi) - 20

link to page 19 link to page 26 link to page 21 RP2040 Datasheet To update part of an IO register, without a read-modify-write sequence, the best solution on RP2040 is atomic set/clear/XOR (see Section 2.1.2). Note that this is more flexible than byte or halfword writes, as any combination of fields can be updated in one operation. Upon a 8-bit or 16-bit write (such as a strb instruction on the Cortex-M0+), an IO register will sample the entire 32-bit write databus. The Cortex-M0+ and DMA on RP2040 will always replicate narrow data across the bus: Pico Examples: https://github.com/raspberrypi/pico-examples/tree/master/system/narrow_io_write/narrow_io_write.c Lines 19 - 60 19 int main() { 20 stdio_init_all(); 21 22 // We'll use WATCHDOG_SCRATCH0 as a convenient 32 bit read/write register 23 // that we can assign arbitrary values to 24 io_rw_32 *scratch32 = &watchdog_hw->scratch[0]; 25 // Alias the scratch register as two halfwords at offsets +0x0 and +0x2 26 volatile uint16_t *scratch16 = (volatile uint16_t *) scratch32; 27 // Alias the scratch register as four bytes at offsets +0x0, +0x1, +0x2, +0x3: 28 volatile uint8_t *scratch8 = (volatile uint8_t *) scratch32; 29 30 // Show that we can read/write the scratch register as normal: 31 printf("Writing 32 bit value\n"); 32 *scratch32 = 0xdeadbeef; 33 printf("Should be 0xdeadbeef: 0x%08x\n", *scratch32); 34 35 // We can do narrow reads just fine -- IO registers treat this as a 32 bit 36 // read, and the processor/DMA will pick out the correct byte lanes based 37 // on transfer size and address LSBs 38 printf("\nReading back 1 byte at a time\n"); 39 // Little-endian! 40 printf("Should be ef be ad de: %02x %02x %02x %02x\n", 41 scratch8[0], scratch8[1], scratch8[2], scratch8[3]); 42 43 // The Cortex-M0+ and the RP2040 DMA replicate byte writes across the bus, 44 // and IO registers will sample the entire write bus always. 45 printf("\nWriting 8 bit value 0xa5 at offset 0\n"); 46 scratch8[0] = 0xa5; 47 // Read back the whole scratch register in one go 48 printf("Should be 0xa5a5a5a5: 0x%08x\n", *scratch32); 49 50 // The IO register ignores the address LSBs [1:0] as well as the transfer 51 // size, so it doesn't matter what byte offset we use 52 printf("\nWriting 8 bit value at offset 1\n"); 53 scratch8[1] = 0x3c; 54 printf("Should be 0x3c3c3c3c: 0x%08x\n", *scratch32); 55 56 // Halfword writes are also replicated across the write data bus 57 printf("\nWriting 16 bit value at offset 0\n"); 58 scratch16[0] = 0xf00d; 59 printf("Should be 0xf00df00d: 0x%08x\n", *scratch32); 60 }
2.1.5. List of Registers
The Bus Fabric registers start at a base address of 0x40030000 (defined as BUSCTRL_BASE in SDK). Table 4. List of
Offset Name Info
BUSCTRL registers 0x00 BUS_PRIORITY Set the priority of each master for bus arbitration. 2.1. Bus Fabric
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Document Outline RP2040 Datasheet Colophon Legal Disclaimer Notice Table of Contents Chapter 1. Introduction 1.1. Why is the chip called RP2040? 1.2. Summary 1.3. The Chip 1.4. Pinout Reference 1.4.1. Pin Locations 1.4.2. Pin Descriptions 1.4.3. GPIO Functions Chapter 2. System Description 2.1. Bus Fabric 2.1.1. AHB-Lite Crossbar 2.1.2. Atomic Register Access 2.1.3. APB Bridge 2.1.4. Narrow IO Register Writes 2.1.5. List of Registers 2.2. Address Map 2.2.1. Summary 2.2.2. Detail 2.3. Processor subsystem 2.3.1. SIO 2.3.2. Interrupts 2.3.3. Event Signals 2.3.4. Debug 2.4. Cortex-M0+ 2.4.1. Features 2.4.2. Functional Description 2.4.3. Programmer’s model 2.4.4. System control 2.4.5. NVIC 2.4.6. MPU 2.4.7. Debug 2.4.8. List of Registers 2.5. DMA 2.5.1. Configuring Channels 2.5.2. Starting Channels 2.5.3. Data Request (DREQ) 2.5.4. Interrupts 2.5.5. Additional Features 2.5.6. Example Use Cases 2.5.7. List of Registers 2.6. Memory 2.6.1. ROM 2.6.2. SRAM 2.6.3. Flash 2.7. Boot Sequence 2.8. Bootrom 2.8.1. Processor Controlled Boot Sequence 2.8.2. Bootrom Contents 2.8.3. USB Mass Storage Interface 2.8.4. USB PICOBOOT Interface 2.9. Power Supplies 2.9.1. Digital IO Supply (IOVDD) 2.9.2. Digital Core Supply (DVDD) 2.9.3. On-Chip Voltage Regulator Input Supply (VREG_VIN) 2.9.4. USB PHY Supply (USB_VDD) 2.9.5. ADC Supply (ADC_AVDD) 2.9.6. Power Supply Sequencing 2.9.7. Power Supply Schemes 2.10. Core Supply Regulator 2.10.1. Application Circuit 2.10.2. Operating Modes 2.10.3. Output Voltage Select 2.10.4. Status 2.10.5. Current Limit 2.10.6. List of Registers 2.10.7. Detailed Specifications 2.11. Power Control 2.11.1. Top-level Clock Gates 2.11.2. SLEEP State 2.11.3. DORMANT State 2.11.4. Memory Power Down 2.11.5. Programmer’s Model 2.12. Chip-Level Reset 2.12.1. Overview 2.12.2. Power-on Reset 2.12.3. Brown-out Detection 2.12.4. Supply Monitor 2.12.5. External Reset 2.12.6. Rescue Debug Port Reset 2.12.7. Source of Last Reset 2.12.8. List of Registers 2.13. Power-On State Machine 2.13.1. Overview 2.13.2. Power On Sequence 2.13.3. Register Control 2.13.4. Interaction with Watchdog 2.13.5. List of Registers 2.14. Subsystem Resets 2.14.1. Overview 2.14.2. Programmer’s Model 2.14.3. List of Registers 2.15. Clocks 2.15.1. Overview 2.15.2. Clock sources 2.15.3. Clock Generators 2.15.4. Frequency Counter 2.15.5. Resus 2.15.6. Programmer’s Model 2.15.7. List of Registers 2.16. Crystal Oscillator (XOSC) 2.16.1. Overview 2.16.2. Usage 2.16.3. Startup Delay 2.16.4. XOSC Counter 2.16.5. DORMANT mode 2.16.6. Programmer’s Model 2.16.7. List of Registers 2.17. Ring Oscillator (ROSC) 2.17.1. Overview 2.17.2. ROSC/XOSC trade-offs 2.17.3. Modifying the frequency 2.17.4. ROSC divider 2.17.5. Random Number Generator 2.17.6. ROSC Counter 2.17.7. DORMANT mode 2.17.8. List of Registers 2.18. PLL 2.18.1. Overview 2.18.2. Calculating PLL parameters 2.18.3. Configuration 2.18.4. List of Registers 2.19. GPIO 2.19.1. Overview 2.19.2. Function Select 2.19.3. Interrupts 2.19.4. Pads 2.19.5. Software Examples 2.19.6. List of Registers 2.20. Sysinfo 2.20.1. Overview 2.20.2. List of Registers 2.21. Syscfg 2.21.1. Overview 2.21.2. List of Registers 2.22. TBMAN 2.22.1. List of Registers Chapter 3. PIO 3.1. Overview 3.2. Programmer’s Model 3.2.1. PIO Programs 3.2.2. Control Flow 3.2.3. Registers 3.2.4. Stalling 3.2.5. Pin Mapping 3.2.6. IRQ Flags 3.2.7. Interactions Between State Machines 3.3. PIO Assembler (pioasm) 3.3.1. Directives 3.3.2. Values 3.3.3. Expressions 3.3.4. Comments 3.3.5. Labels 3.3.6. Instructions 3.3.7. Pseudoinstructions 3.4. Instruction Set 3.4.1. Summary 3.4.2. JMP 3.4.3. WAIT 3.4.4. IN 3.4.5. OUT 3.4.6. PUSH 3.4.7. PULL 3.4.8. MOV 3.4.9. IRQ 3.4.10. SET 3.5. Functional Details 3.5.1. Side-set 3.5.2. Program Wrapping 3.5.3. FIFO Joining 3.5.4. Autopush and Autopull 3.5.5. Clock Dividers 3.5.6. GPIO Mapping 3.5.7. Forced and EXEC’d Instructions 3.6. Examples 3.6.1. Duplex SPI 3.6.2. WS2812 LEDs 3.6.3. UART TX 3.6.4. UART RX 3.6.5. Manchester Serial TX and RX 3.6.6. Differential Manchester (BMC) TX and RX 3.6.7. I2C 3.6.8. PWM 3.6.9. Addition 3.6.10. Further Examples 3.7. List of Registers Chapter 4. Peripherals 4.1. USB 4.1.1. Overview 4.1.2. Architecture 4.1.3. Programmer’s Model 4.1.4. List of Registers References 4.2. UART 4.2.1. Overview 4.2.2. Functional description 4.2.3. Operation 4.2.4. UART hardware flow control 4.2.5. UART DMA Interface 4.2.6. Interrupts 4.2.7. Programmer’s Model 4.2.8. List of Registers 4.3. I2C 4.3.1. Features 4.3.2. IP Configuration 4.3.3. I2C Overview 4.3.4. I2C Terminology 4.3.5. I2C Behaviour 4.3.6. I2C Protocols 4.3.7. Tx FIFO Management and START, STOP and RESTART Generation 4.3.8. Multiple Master Arbitration 4.3.9. Clock Synchronization 4.3.10. Operation Modes 4.3.11. Spike Suppression 4.3.12. Fast Mode Plus Operation 4.3.13. Bus Clear Feature 4.3.14. IC_CLK Frequency Configuration 4.3.15. DMA Controller Interface 4.3.16. Operation of Interrupt Registers 4.3.17. List of Registers 4.4. SPI 4.4.1. Overview 4.4.2. Functional Description 4.4.3. Operation 4.4.4. List of Registers 4.5. PWM 4.5.1. Overview 4.5.2. Programmer’s Model 4.5.3. List of Registers 4.6. Timer 4.6.1. Overview 4.6.2. Counter 4.6.3. Alarms 4.6.4. Programmer’s Model 4.6.5. List of Registers 4.7. Watchdog 4.7.1. Overview 4.7.2. Tick generation 4.7.3. Watchdog Counter 4.7.4. Scratch Registers 4.7.5. Programmer’s Model 4.7.6. List of Registers 4.8. RTC 4.8.1. Storage Format 4.8.2. Leap year 4.8.3. Interrupts 4.8.4. Reference clock 4.8.5. Programmer’s Model 4.8.6. List of Registers 4.9. ADC and Temperature Sensor 4.9.1. Features 4.9.2. ADC controller 4.9.3. SAR ADC 4.9.4. Temperature Sensor 4.9.5. List of Registers 4.10. SSI 4.10.1. Overview 4.10.2. Features 4.10.3. IP Modifications 4.10.4. Clock Ratios 4.10.5. Transmit and Receive FIFO Buffers 4.10.6. 32-Bit Frame Size Support 4.10.7. SSI Interrupts 4.10.8. Transfer Modes 4.10.9. Operation Modes 4.10.10. Partner Connection Interfaces 4.10.11. DMA Controller Interface 4.10.12. APB Interface 4.10.13. List of Registers Chapter 5. Electrical and Mechanical 5.1. Package 5.1.1. Recommended PCB Footprint 5.1.2. Compliance 5.2. Pinout 5.2.1. Pin Locations 5.2.2. Pin Definitions 5.2.3. Pin Specifications 5.3. Power Supplies 5.4. Power Consumption 5.4.1. Power Consumption versus frequency Appendix A: Register Field Types Standard types RW RO WO Clear types SC WC FIFO types RF WF RWF Appendix B: Errata Bootrom RP2040-E9 Clocks RP2040-E7 RP2040-E10 GPIO / ADC RP2040-E6 USB RP2040-E2 RP2040-E3 RP2040-E4 RP2040-E5 Watchdog RP2040-E1 XIP Flash RP2040-E8 Appendix C: Documentation Release History