Registered: Jun 2000
Location: Sunnyvale, CA
Posts: 216

Does anyone know if the Visor USB port a low speed one, i.e. 1.5Mbps, or high speed, 12Mbps?

I would like to know becuase I'm getting a new Mac and want to hook all my low speed USB devices - keyboard, mouse, etc... - to the one port, and the high speed devices to the other port. (The newer Macs have two independant USB controllers - one for each port.)

Thanks in advance.

Registered: Dec 1999
Location: Connecticut USA
Posts: 2682

This is from the Handspring Developer's Kit manual:

quote:

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The Cradle Connector contains two serial buses that communicate with external devices: a USB bus and a simple serial bus. The high-speed USB interface is a slave-only interface, providing a payload bandwidth of up to 400 Kbps between a host PC or Mac and the handheld device. The serial port provides asynchronous capability to low-speed devices (9600 Kbps or less).

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God bless America, my home sweet home...

Registered: Jan 2000
Location:
Posts: 434

Which just goes to show that even monkeys fall out of trees. Surely Handspring meant to say: "The serial port provides asynchronous capability to low-speed devices (9600 bps or less)."

Registered: Jun 2000
Location: Sunnyvale, CA
Posts: 216

9600Kpbs! I wish!

It's 9600bps. I didn't even notice that typo last night when I read Mark's reply.

Anyway, the Handspring Dev. Kit Manual says that the "payload" bandwidth is 400Kbps. Unfortunately this doesn't tell me what the base USB rate is.

A 400Kpbs payload bandwidth is still well within the 1.5Mbps base data rate of a low speed USB device.

It's this base data rate that I'm interested in. Low speed devices, if combined with high speed devices on the same USB host controller, will take up 8 times the bandwidth as the high speed devices. It's like the low speed devices are transmitting 8 times the data.

For keyboards, mice, game controllers, etc... their data payloads are so small that this really does not matter. But a Visor Hotsync - especially with AvantGo - can be as high as hundreds of Kbytes. So if the Visor runs at low speed, this would seriously effect any high speed devices on the same USB bus.

Maybe I'm just over optimizing here, but I'm also a very curious person.

Registered: Feb 2000
Location:
Posts: 638

quote:

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Originally posted by MPM
9600Kpbs! I wish!

It's 9600bps. I didn't even notice that typo last night when I read Mark's reply.

Anyway, the Handspring Dev. Kit Manual says that the "payload" bandwidth is 400Kbps. Unfortunately this doesn't tell me what the base USB rate is.

A 400Kpbs payload bandwidth is still well within the 1.5Mbps base data rate of a low speed USB device.

It's this base data rate that I'm interested in. Low speed devices, if combined with high speed devices on the same USB host controller, will take up 8 times the bandwidth as the high speed devices. It's like the low speed devices are transmitting 8 times the data.

For keyboards, mice, game controllers, etc... their data payloads are so small that this really does not matter. But a Visor Hotsync - especially with AvantGo - can be as high as hundreds of Kbytes. So if the Visor runs at low speed, this would seriously effect any high speed devices on the same USB bus.

Maybe I'm just over optimizing here, but I'm also a very curious person.

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