cubeberg 540 Posted May 23, 2013 Share Posted May 23, 2013 Helpful hint - if you want to keep from running the emulation side of the board - pull the VCC AND RST jumper - otherwise your chip won't start up. Drove me crazy this weekend spirilis 1 Quote Link to post Share on other sites
spirilis 1,265 Posted May 23, 2013 Share Posted May 23, 2013 Helpful hint - if you want to keep from running the emulation side of the board - pull the VCC AND RST jumper - otherwise your chip won't start up. Drove me crazy this weekend Lol, that has driven me nuts before... the parasitic draw through the RST line! Quote Link to post Share on other sites
cubeberg 540 Posted May 23, 2013 Share Posted May 23, 2013 Lol, that has driven me nuts before... the parasitic draw through the RST line! It actually seems like there's something else going on as well - the resistance between VCC and the reset pin changed, and the voltage on the reset line was too low. I was getting 3.6v on VCC, but my program wasn't starting. I'm wondering if there's a pull-up on both sides of the board for some reason. Quote Link to post Share on other sites
spirilis 1,265 Posted May 23, 2013 Share Posted May 23, 2013 It actually seems like there's something else going on as well - the resistance between VCC and the reset pin changed, and the voltage on the reset line was too low. I was getting 3.6v on VCC, but my program wasn't starting. I'm wondering if there's a pull-up on both sides of the board for some reason.Probably voltage drop from the F1611 in the emulator draining current through its pin's protection diode into its own (0V in this state) Vcc rail? Quote Link to post Share on other sites
cubeberg 540 Posted May 23, 2013 Share Posted May 23, 2013 Probably voltage drop from the F1611 in the emulator draining current through its pin's protection diode into its own (0V in this state) Vcc rail? Hm - that sounds more likely than TI putting an extra resistor on - I'll have to take a look and see if I can figure it out. Quote Link to post Share on other sites
spirilis 1,265 Posted May 23, 2013 Share Posted May 23, 2013 Hm - that sounds more likely than TI putting an extra resistor on - I'll have to take a look and see if I can figure it out. I saw your other post, you saw ~1.4V ... That just happens to be 2 * 0.7V (typical drop over a diode), so I'm thinking it's something related to that. cubeberg 1 Quote Link to post Share on other sites
cubeberg 540 Posted May 23, 2013 Share Posted May 23, 2013 I saw your other post, you saw ~1.4V ... That just happens to be 2 * 0.7V (typical drop over a diode), so I'm thinking it's something related to that. Awesome - thanks! Quote Link to post Share on other sites
spirilis 1,265 Posted May 23, 2013 Share Posted May 23, 2013 Awesome - thanks! Basically this sort of thing happens any time you have two connected devices where one isn't powered, I discovered this the hard way with my grill monitor (as it shuts off Vcc to the MAX31855 thermocouple drivers)... Supposedly the proper solution to this (for future reference/education) is a "bus interface" IC, something like this: http://www.idt.com/products/memory-logic/bus-switch/33v-quickswitch-high-bandwidth-bus-switch/qs3vh245-quickswitch-products-33v-8-bit-bus-switch-hot-swap-applications That came from the Renesas YRPBRX210 board, its onboard SEGGER J-Link emulator talks to it through one of those, that board is designed to be powered over USB (in which case J-Link is active) or via CR2032 battery, in which case the J-Link is unpowered, so such an interface is needed to ensure the RX's I/O pins don't try to back-power the J-Link's MCU through that method... Naturally I don't fault TI for leaving that out since the LP is meant to be super low cost You might also want to yank the UART pins since one of those could trigger if you happen to use the MSP430's TX pin for something else (the moment it goes 'high' it'll start trying to power the TUSB3410 I bet) cubeberg 1 Quote Link to post Share on other sites
cubeberg 540 Posted May 23, 2013 Share Posted May 23, 2013 Hm - good to know. Looks like TI makes some as well - http://www.ti.com/product/sn74cbt1g125 Quote Link to post Share on other sites
PTB 27 Posted June 2, 2013 Share Posted June 2, 2013 Just a quick little update to my previous "NoobReview". Finally got the headers and time to solder them on. Plugged it in and.... Look Ma... No wires. This is a Stellaris => Bluehash Booster Booster => RobG touchscreen stack. On a full charge, I just let it sit there and it ran for about 2:30 hours before it started getting dim. At 2:50 hours it was very dim and I tried the touchscreen, but it was by then unresponsive but you could still read the display. So that's a pretty decent run with the backlight on the whole time. I may get a bigger battery and see how long I can stretch it out. Anyway..... that's pretty much it. Cheers PTB bluehash 1 Quote Link to post Share on other sites
bluehash 1,581 Posted June 2, 2013 Author Share Posted June 2, 2013 Thanks PTB.. a higher mAH battery will work. Quote Link to post Share on other sites
bluehash 1,581 Posted December 29, 2013 Author Share Posted December 29, 2013 Back at this again. I've incorporated the following for a new version of the BoosterPack. A cursory check would be appreciated. Support for 20 and 40 pin XL Boosterpacks Solder pads changed to through hole pads for external battery. Change vertical conector to JST right angle connector. This allows stacking as well as the right pinout for the battery Add support for CR2450 rechargable coin cell. Monitor battery voltage via AIN0( P1.0) Solder jumper for AIN0 Specs are same as before: 3.3V, 120mA output. New design: Before: PTB, dubnet, spirilis and 1 other 4 Quote Link to post Share on other sites
PTB 27 Posted December 29, 2013 Share Posted December 29, 2013 Hi Bluehash, Nice !!! Would 3mm mounting holes be useful? Cheers PTB Quote Link to post Share on other sites
bluehash 1,581 Posted December 29, 2013 Author Share Posted December 29, 2013 Hi Bluehash, Nice !!! Would 3mm mounting holes be useful? Cheers PTB @@PTB Sorry, can you elaborate? Quote Link to post Share on other sites
PTB 27 Posted December 29, 2013 Share Posted December 29, 2013 Hi Bluehash, Just thinking would be nice to have some mounting holes. If this was the lowest board in a stack, it could be screwed down into a case or onto something. Then the whole board sandwich of battery booster pack, launchpad, plus any additional boosters would be mountable via your booster pack. Just a thought, if you think its not of value or will create problems please ignore. Cheers PTB bluehash 1 Quote Link to post Share on other sites
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