Hi
Has anyone implemented USBOTG using ISP1301 on the LPC17xx range?
I am looking for a simple virtual com port solution...
Regards Mark
Do you mean this: www.stericsson.com/.../245493.jsp
Note that they say it's, "in our Portfolio Archive and for reference use only" - presumably meaning that it's not recommended for new designs?
ISP1301 was developed by NXP first, and was sold to ST-Ericsson. ST-Ericsson seems to discontinue the division.
ISP1301 is one of "old standard" FS/LS OTG transceiver. The circuit example and OTG description on LPC17xx reference manual suggest that LPC17xx uses it to support additional protocols for OTG, like SRP, HNP. ie. within the range of standard usage of the chip. For this purpose, other standard OTG transceiver, from ST (STOTG04E). etc. is functionary compatible.
The board of "IAR KickStart Kit for LPC1768" mounts ISP1301. I'm not sure IAR provides any OTG example using ISP1301 or not. Ask it to IAR.
Tsuneo
There is an option, host/device switch, other than OTG using ISP1301. In this option, USB D+/D- lines from A and B USB receptacles are switched by analog switches, to connect to single-pair D+/D- pins of LPC17xx.
Analog switches for FS/LS USB line,
Switching in USB Consumer Applications - Analog Devices www.analog.com/.../usb_switch.html
ON semiconductor www.onsemi.com/.../parametrics.do
Fairchild www.fairchildsemi.com/.../USBGuide_ENG_pgs.pdf
Depending on your target application, this dual-role implementation may be better than OTG. Also, this implementation makes your firmware simple, because OTG-specific protocols are not required to code in.