BENGuin
Newbie level 1
compactflash hotplug
I’ve got a project that requires implementing on a carrier board a hot-pluggable compact flash slot connected to a non hot-pluggable True IDE compact flash slot of a Computer On Module. The primary challenge is electrically isolating the host bus from transients from the card during insertion/removal.
Alternatively, I’ve looked for PCI and USB implementations of CF but found none that meet the requirements of hot plug, industrial temperature, and sold/supported for low production volumes (<500/year)
So my intended solution is to use a simple bus isolation chip to connect to the True IDE lines, which is also a bus connecting the processor to an FPGA, memory etc. I would use the CF Card Detect signals as inputs to an FPGA function which will enable FETs to provide the CF card Vcc, then after waiting for a card power up delay, enable the bus isolation chip. CD will also cause the bus to go hiZ and the FETs to turn off upon card removal.
Bus isolation chips are plentiful, TI, Fairchild, AD, and Pericom all have certain flavours available, but none seem to provide a useful application circuit for compact flash. TI has BGA package solutions with built in Card Detect circuitry but I’d like to have a solution that will work on a double layer board.
So my questions are:
1. Does this seem viable to anyone who may have implemented such a thing before?
2. Can anyone direct me to useful application notes/circuits for this arrangement?
3. More of a SW question – any predictions of how much grief the SW team will have building a driver for a TrueIDE slot that allows hot plug? I expect mounting and un-mounting will be the chief concern. It will be a Green Hills OS on an MPC8347E
Any help is much appreciated.
I’ve got a project that requires implementing on a carrier board a hot-pluggable compact flash slot connected to a non hot-pluggable True IDE compact flash slot of a Computer On Module. The primary challenge is electrically isolating the host bus from transients from the card during insertion/removal.
Alternatively, I’ve looked for PCI and USB implementations of CF but found none that meet the requirements of hot plug, industrial temperature, and sold/supported for low production volumes (<500/year)
So my intended solution is to use a simple bus isolation chip to connect to the True IDE lines, which is also a bus connecting the processor to an FPGA, memory etc. I would use the CF Card Detect signals as inputs to an FPGA function which will enable FETs to provide the CF card Vcc, then after waiting for a card power up delay, enable the bus isolation chip. CD will also cause the bus to go hiZ and the FETs to turn off upon card removal.
Bus isolation chips are plentiful, TI, Fairchild, AD, and Pericom all have certain flavours available, but none seem to provide a useful application circuit for compact flash. TI has BGA package solutions with built in Card Detect circuitry but I’d like to have a solution that will work on a double layer board.
So my questions are:
1. Does this seem viable to anyone who may have implemented such a thing before?
2. Can anyone direct me to useful application notes/circuits for this arrangement?
3. More of a SW question – any predictions of how much grief the SW team will have building a driver for a TrueIDE slot that allows hot plug? I expect mounting and un-mounting will be the chief concern. It will be a Green Hills OS on an MPC8347E
Any help is much appreciated.
