USB ZX chips?

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dlh
Posts: 395
Joined: 15 December 2006, 12:12 PM
Location: ~Cincinnati

Post by dlh »

I guess this should be in the Beating a Dead Horse Forum but...

Microchip has a USB stack which works with the PIC18F2550/4550 (28/40 pin) for CDC and they also provide Virtual COM Port drivers for Windows/Linux/OSX. It's fairly simple to link it with your code - even using PicBasic Pro. Here are their specs...
Universal Serial Bus Features:
• USB V2.0 Compliant
• Low Speed (1.5 Mb/s) and Full Speed (12 Mb/s)
• Supports Control, Interrupt, Isochronous and Bulk Transfers
• Supports up to 32 Endpoints (16 bidirectional)
• 1 Kbyte Dual Access RAM for USB
• On-Chip USB Transceiver with On-Chip Voltage Regulator
• Interface for Off-Chip USB Transceiver
• Streaming Parallel Port (SPP) for USB streaming transfers (40/44-pin devices only)
The drawbacks - the chips have 1/8 the Flash/Ram of Atmel chips and run one instruction for every four clock cycles which is like living in the Middle Ages compared to Atmel.

What I do not understand is why Microchip can do this on their rather primitive chips but Atmel cannot (or will not).
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dkinzer
Site Admin
Posts: 3120
Joined: 03 September 2005, 13:53 PM
Location: Portland, OR

Post by dkinzer »

dlh wrote:What I do not understand is why Microchip can do this on their rather primitive chips but Atmel cannot (or will not).
The Microchip parts that support the USB stack have on-board USB hardware. There are AVR chips that have on-board USB hardware (AT90USB1286 or ATmega32U4 for example). There is also an open source USB stack called LUFA for the AVR USB parts.
- Don Kinzer
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