System Controller (Syscon)

The System Controller provides a read-only identification and configuration register block. Software can query compile-time SoC parameters at runtime: vendor, platform, product, silicon revision, feature flags, reference clock frequency, and build timestamp.

All registers are constants derived from elaboration-time Parameter values. No write access is defined; bus writes are silently ignored.

Features

• IP Identification block (header + version at 0x000-0x007)

• 32-bit identity register: vendor, platform, product, and platform class

• Silicon revision register: major and minor revision

• UNIX build timestamp register (seconds since epoch)

• Reference clock frequency register (Hz)

• Feature flag words: bit N set when the Feature element with ordinal N is present

• Supported buses: APB3, TileLink, Wishbone

Parameters

Parameter	Default	Description
vendor	(required)	Vendor identifier (Vendor enum)
platform	(required)	Platform identifier (Platform enum)
platformClass	(required)	Platform class (PlatformClass enum): NonMetal (MCU) or Alkali (MPU)
product	(required)	Product identifier (Product enum)
refClockHz	(required)	Board reference oscillator frequency in Hz
siliconMajor	0	Silicon major revision
siliconMinor	1	Silicon minor revision
features	List()	Feature flags to set in the features register
buildDate	env BUILD_DATE or now	UNIX timestamp (seconds). Read from the BUILD_DATE environment variable if set, otherwise captured at elaboration time

Register Map

Offset	Name	Description
0x000	ip_header	IP Identification header (API, length, IP ID)
0x004	ip_version	IP Identification version (major, minor, patch)
0x008	identity	SoC identity (see below)
0x00C	silicon_rev	Silicon revision: major in [31:16], minor in [15:0]
0x010	build_date	Build UNIX timestamp (seconds)
0x014	ref_clock	Reference oscillator frequency (Hz)
0x018	feature_info	Number of feature words in [7:0]
0x01C	features[n]	Feature words, one per 32 Feature ordinals (see below)

Identity Register (0x008)

Bits	Field	Description
[31:24]	platformClass	Platform class ordinal (0=NonMetal/MCU, 1=Alkali/MPU)
[23:16]	product	Product ordinal (0=ElemRV)
[15:8]	platform	Platform ordinal (0=Hydrogen, 1=Carbon, 2=Nitrogen, 3=Oxygen, 4=Phosphorus, 5=Sulfur)
[7:0]	vendor	Vendor ordinal (0=AescSilicon)

Feature Words (0x01C)

features[N / 32] bit N % 32 is set when the Feature element with ordinal N appears in the features parameter list. The SoC builder populates this list automatically by collecting sysconFeatures from each IP on the bus.

Bit	Feature	Description
0	I2c	I2C controller or device present
1	Spi	SPI controller or device present
2	Uart	UART present
3	Gpio	GPIO present
4	Pio	Programmable I/O present
5	Pwm	PWM present
6	Pinmux	Pin multiplexer present
7	Clock	Clock controller present
8	Esm	Error Signaling Module present
9	Mailbox	Mailbox present
10	Mtimer	Machine-mode timer present
11	Timer	General-purpose timer present
12	Plic	Platform-level interrupt controller present
13	Reset	Reset controller present
14	Semaphore	Hardware semaphore present
15	Watchdog	Watchdog timer present
16	Aes	AES accelerator present
17	Crc	CRC engine present
18	Prng	Pseudo-random number generator present
19	Hyperbus	HyperBus interface present
20	Ocram	On-chip SRAM controller present
21	SpiFlash	SPI flash controller present
22	Dma	DMA controller present

Software

The bare-metal driver is software/driver/syscon.c with software/include/syscon.h. The register block and all ordinals are in software/include/syscon_defs.h, which is generated from the Scala sources: after changing the register map or an enum in SocIds.scala, run

sbt "runMain nafarr.GenerateHeaders"

and commit the updated header. CI fails if the committed header differs from the generated one.