Ryan Malloy
b21f4957f6
Astro 5 + Starlight 0.37 site at site/ with teal/steel theme. Content sourced from 14 reverse engineering docs, master reference, and custom firmware source. Includes Tabs, Badge, Steps, Aside, FileTree, and CardGrid components throughout. DiSEqC SVGs with click-to-zoom via starlight-image-zoom. All internal links validated. Pagefind search indexes all 32 pages.
95 lines
5.8 KiB
Plaintext
95 lines
5.8 KiB
Plaintext
---
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title: Hardware Overview
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description: Board layout, chip identification, supported modulations, and architecture of the Genpix SkyWalker-1 DVB-S USB 2.0 receiver.
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---
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import { Tabs, TabItem, Badge, Aside, CardGrid, Card } from '@astrojs/starlight/components';
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The Genpix SkyWalker-1 is a standalone USB 2.0 DVB-S satellite receiver built around two primary ICs: a Cypress FX2LP USB microcontroller and a Broadcom BCM4500 satellite demodulator. The FX2 handles all USB communication, LNB control, and DiSEqC signaling, while the BCM4500 performs RF demodulation, forward error correction, and outputs an MPEG-2 transport stream on an 8-bit parallel bus.
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## Core Components
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| Component | Part Number | Role |
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|-----------|-------------|------|
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| MCU | Cypress CY7C68013A (FX2LP) | USB 2.0 Hi-Speed controller, 8051 core at 48 MHz |
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| Demodulator | Broadcom BCM4500 | DVB-S / Turbo / DCII / DSS demodulator, 128-pin MQFP |
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| EEPROM | 24Cxx-family (I2C address 0x51) | FX2 firmware storage, serial number, calibration data |
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| Tuner/LNB | Unknown IC (I2C address 0x10) | Tuner or LNB controller on shared I2C bus |
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## Board Block Diagram
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```
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+--[ I2C EEPROM 0x51 ]
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USB 2.0 HS | I2C Bus (400 kHz)
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Host PC <----> [ CY7C68013A FX2LP ] <-----> [ BCM4500 Demod 0x08 ]
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| 8051 @ 48 MHz | |
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| GPIF Engine |<-----------+ 8-bit parallel TS
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| EP2 Bulk IN |
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| GPIO (P0/P3) |---> [ 22 kHz Osc ] ---> LNB/Coax
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| |---> [ LNB Voltage Ctrl ]
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+-----------------+
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+--[ Tuner/LNB IC 0x10 ]
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```
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The GPIF engine inside the FX2 transfers the BCM4500's transport stream output directly into USB bulk endpoint EP2 with zero firmware intervention in the data path. This hardware-managed pipeline provides approximately 5x bandwidth headroom over the maximum DVB-S transport stream rate.
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## Supported Modulations
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| Index | Modulation | Constant | FEC Family |
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|-------|-----------|----------|------------|
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| 0 | DVB-S QPSK <Badge text="Standard" variant="note" /> | `ADV_MOD_DVB_QPSK` | Viterbi + Reed-Solomon |
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| 1 | Turbo-coded QPSK <Badge text="Turbo" variant="success" /> | `ADV_MOD_TURBO_QPSK` | Turbo |
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| 2 | Turbo-coded 8PSK <Badge text="Turbo" variant="success" /> | `ADV_MOD_TURBO_8PSK` | Turbo |
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| 3 | Turbo-coded 16QAM <Badge text="Turbo" variant="success" /> | `ADV_MOD_TURBO_16QAM` | Turbo |
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| 4 | Digicipher II Combo <Badge text="DCII" variant="caution" /> | `ADV_MOD_DCII_C_QPSK` | DCII |
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| 5 | Digicipher II I-stream (split) <Badge text="DCII" variant="caution" /> | `ADV_MOD_DCII_I_QPSK` | DCII |
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| 6 | Digicipher II Q-stream (split) <Badge text="DCII" variant="caution" /> | `ADV_MOD_DCII_Q_QPSK` | DCII |
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| 7 | Digicipher II Offset QPSK <Badge text="DCII" variant="caution" /> | `ADV_MOD_DCII_C_OQPSK` | DCII |
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| 8 | DSS QPSK <Badge text="DSS" variant="note" /> | `ADV_MOD_DSS_QPSK` | Viterbi + Reed-Solomon |
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| 9 | DVB-S BPSK <Badge text="Standard" variant="note" /> | `ADV_MOD_DVB_BPSK` | Viterbi + Reed-Solomon |
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<Aside type="caution" title="DVB-S2 Not Supported">
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DVB-S2 is **not** supported by the SkyWalker-1. This is a fundamental hardware limitation of the BCM4500 demodulator silicon -- it was designed before the DVB-S2 standard was ratified (March 2005) and contains no LDPC or BCH decoder hardware. No firmware update can add DVB-S2 support. See the [DVB-S2 Incompatibility](/driver/dvb-s2/) page for the full technical analysis.
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</Aside>
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## Architecture Overview
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<CardGrid>
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<Card title="USB Interface" icon="laptop">
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EP0 for vendor commands (tuning, LNB control, status). EP2 for bulk MPEG-2 transport stream data. VID `0x09C0`, PID `0x0203`. See [USB Interface](/usb/interface/).
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</Card>
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<Card title="BCM4500 Demodulator" icon="seti:config">
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Indirect register access via I2C (0xA6/0xA7/0xA8 protocol). Two FEC decoder paths: turbo codes and legacy Viterbi/Reed-Solomon. See [Demodulator Interface](/bcm4500/demodulator/).
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</Card>
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<Card title="GPIF Streaming" icon="right-arrow">
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Hardware-managed data path. 8-bit parallel bus from BCM4500 to EP2 FIFO via GPIF master read. AUTOIN auto-commits full packets to USB. See [GPIF Streaming](/bcm4500/gpif-streaming/).
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</Card>
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<Card title="I2C Bus" icon="setting">
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400 kHz bus connecting FX2 to BCM4500 (0x08), tuner IC (0x10), and EEPROM (0x51). Bit-banged DiSEqC on separate GPIO pins. See [I2C Bus Architecture](/i2c/bus-architecture/).
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</Card>
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</CardGrid>
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## FEC Architecture
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The BCM4500 contains two distinct FEC decoder paths:
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1. **Advanced Modulation Turbo FEC Decoder** -- Iterative turbo code decoder supporting QPSK (rates 1/4, 1/2, 3/4), 8PSK (rates 2/3, 3/4, 5/6, 8/9), 16QAM (rate 3/4), with Reed-Solomon (t=10) outer code.
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2. **Legacy DVB/DIRECTV/DCII-Compliant FEC Decoder** -- Concatenated Viterbi inner decoder (convolutional code, rates 1/2 through 7/8) plus Reed-Solomon outer decoder.
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There is no LDPC or BCH decoder hardware. The turbo FEC codes are Broadcom/EchoStar proprietary and are not part of any open standard.
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## Firmware
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The SkyWalker-1 boots from an on-board I2C EEPROM containing firmware in Cypress C2 format. No host-side firmware files are required. Multiple stock firmware versions have been identified:
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| Firmware | Version ID | Build Date | Notes |
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|----------|-----------|------------|-------|
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| v2.06.04 | 0x020604 | 2007-07-13 | Original release, 61 functions |
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| v2.13.01 | 0x020D01 | 2010-03-12 | Latest revision, 82-88 functions |
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| Custom v3.01.0 | 0x030100 | 2026-02-12 | Open-source SDCC + fx2lib, RAM-loaded |
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See [Firmware Version Comparison](/firmware/version-comparison/) for a full analysis of the differences between stock firmware versions.
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