X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=Notebook;h=457029a30d4ef61ad40c52ce12dfeae96d671c44;hb=ebb705e712cc6f4cfcf48153eb73cd380a5b9850;hp=ab111a417377d4b9b71b0b6bd13b307e8112c89e;hpb=168fc1c7cf9ea0a4a7fb2144a21d1d63be0f4181;p=hw%2Ftelemetrum

diff --git a/Notebook b/Notebook
index ab111a4..457029a 100644
--- a/Notebook
+++ b/Notebook
@@ -105,8 +105,12 @@
   Keith found gps active antennas with cable to U.FL connectors and Molex sells
   cables with U.FL to bare leads, so this should cover the bases.
 
-- TelePyro doesn't need a CPU.  How about an SPI to I2C converter chip with
-  GPIO lines and an I2C ADC chip?
+- TelePyro doesn't really need a CPU.  How about an SPI to I2C converter chip 
+  with GPIO lines and an I2C ADC chip?  Cheaper and easier than a PIC?
+
+	PIC16F882 in SSOP-28 is $2.10 per, 1.41 @ 25 units
+	  -- PIC16F883 is $2.12, PIC16F886 is $2.32, have better memories
+	CP2120 in QFN-20 is     $2.41 per, 2.27 @ 25 units
 
   The Silabs CP2120 has 8 gpio lines but is only available in QFN20.  The NXP
   part I discovered earlier, the SC18IS600, has 4 full gpio lines and 2 lame-o
@@ -143,3 +147,60 @@
 - another way to think about all this is that I could panelize a set of boards
   all done in 2 layers, then treat that as a sub-panel I put N copies down of
   to fill up a 33each.com max panel size.
+
+2009.10.16
+- move to AT45DB161D 16-megabit SPI "DataFlash" EEPROM from Atmel?
+	AT45DB161D-SU-ND in SOIC-8 for $2.26 each
+  appears to compare favorably against $4.40 for current 128kx8 part
+  minor concern about write power, but probably red herring
+
+2010.02.08
+- looking at LiPo charger alternatives
+
+	MAX8808		DFN8, not carried by DK
+	MAX8814		DFN8, not carried by DK
+
+	LTC4095		DFN8, LTC4095EDC#TRMPBFCT-ND 2.91 2.34@100
+		950mA, resistor current set, rate limit input, suspend input,
+		NTC thermal control option, smart CHRG led with 4 states
+	LTC4065		DFN6, LTC4065EDC#TRMPBFCT-ND 2.77 2.23@100
+		750mA, resistor current set, CHRG led, enable input
+	LTC4065A	DFN6, LTC4065AEDC#TRMPBFCT-ND 2.77 2.23@100
+		750mA, resistor current set, CHRG led, supply present out
+		
+	MCP73811	SOT23-5, MCP73811T-420I/OTCT-ND 0.63@1 0.39@100
+		input selects 85 vs 450mA charge current
+
+	MCP73837	DFN10, MCP73837T-FCI/MFCT-ND 1.37@1 0.85@100
+		usb rate select, power good output, dual inputs, dual status
+
+	LX2206		DFN10, LX2206CT-ND 2.68@1 2.01@100
+		rate select, power good output... needs more passives?
+
+	LM3658		DFN10, 
+		dual input, dual rate, two status outputs .. not obvious win
+
+	MCP73855	DFN10, MCP73855T-I/MFCT-ND 1.85@1 1.18@100
+		see Microchip app note 971
+
+
+  Talking to Keith, there's no reason we couldn't use an 8-pin PIC to augment
+  a standalone LiPo charger, implementing a timer after vusb application 
+  before switching the regulator to high current, to allow the cc1111 time to
+  finish the USB bus negotiation phase.  We could also monitor various state
+  bits and multiplex signaling onto one LED.  A combo like the MCP73837 plus
+  a PIC10F206 or 220 would net under $1.50 at 100 pieces and be pretty 
+  powerful.  Since the PIC has avilable weak pull-ups on the gpio lines, the
+  open-drain state outputs from the regulator don't need resistors to be read.
+
+2011.01.17
+- v1.0 and v1.1 boards have a minor error in that the v_lipo sampling resistors
+  are on "the wrong side of the cut" if you try to use a separate pyro battery.
+  The workaround is to cut that trace and put in a jumper, which pretty much
+  requires "return to Bdale for rework".  We should fix this for a future PCB
+  revision.
+
+2011.09.12
+- chatted with Adrian some yesterday.  He likes a Bosch pressure sensor that
+  is DK 828-1005-1-ND .. i2c output, similar range to our current part but
+  smaller, around $5 at our build quantities.