Extremely hot Coldfire in Zoom kit.

peddamat — Fri, 12 May 2006 09:10:37 GMT

Hi everyone,

I just got my hands on a shiny, new Zoom dev kit and noticed the Coldfire processor gets very, very hot. Hot enough that I'm worried about inserting a CF card in the CF adaptor, lest I melt the card and the board. How hot is the processor supposed to get?

Other than the heat, the kit is great.

Sumanth Peddamatham

Re: Extremely hot Coldfire in Zoom kit.

DavidS — Thu, 18 May 2006 20:16:42 GMT

Hi Sumanth,

He are some engineering power numbers....yes it runs hot.

The following numbers where measured on a MCF5475 running at 66/132/264 MHz at room temperature.

Instructions in Flash (Flexbus, 3.3V IO)
Data in external SRAM (Flexbus, 3.3V IO)
SDRAM drive turned on to 8mA drive strength

Caches on

DMA moving data from external SRAM to FEC FIFO
FEC continually transmitting data at 10Mbps / half-duplex
CPU alternates reads of SDRAM and internal registers
---------------------------------
1.48V Core     557 mA    .824W
2.50V DDR      227 mA    .568W
3.27V uP I/O    31 mA    .101W
                       ---------
                        1.493W

Note these are only the power measurements for the voltage rails into the processor. The external memory power budgets are not accounted for here.

I can tell you that the non-encryption parts require ~135mA less on the 1.5V power supply; This saves about 200 mWatts.

Regards, David

topic Extremely hot Coldfire in Zoom kit. in ColdFire/68K Microcontrollers and Processors

Extremely hot Coldfire in Zoom kit.

Re: Extremely hot Coldfire in Zoom kit.