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diff --git a/recipes/sccd/files/README b/recipes/sccd/files/README new file mode 100644 index 0000000000..d2d1934dd4 --- /dev/null +++ b/recipes/sccd/files/README @@ -0,0 +1,220 @@ + Iomega G2 MC68HC908QY4 Support Notes + October 2006 + +The Iomega G2 Version 3.x and 5.x boards have a secondary microcontroller +aboard, a Freescale MC68HC908QY4. This microcontroller is connected to the +board's LED, fan, digital thermometer, power switch, and main processor, the +MPC8241. The connection to the main processor is through the 8241's second +UART and possibly its reset lines. + +The microcontroller can perform the following functions: + o The LED can be set to off, blue, red, blue flash, red flash, + alternate (blue->red->blue) and some boards alternate3 + (blue->blue->blue->red->red->red). The flash and alernate rates + can be be set. Alternate3 rate is fixed. + o Fan can be set to on or auto. Auto mode is a thermostat function + that turns the fan on and off based on two temprature settings: + Fan Temp High and Fan Temp Low. + o The system can be reset, causing a MPC8241 reset, or stopped, + causing a full power down. + o The microcontroller can detect if the soft power switch has been + activated. There appears to a 20s delay after the power switch + has been depressed before the microcontroller causes an actual + power off. This event can be detected by polling the + microcontroller. + +The running system communicates with microcontroller and ultimately controls +the devices connected to it via the MPC8241's second UART. The connection +settings are: 9600,8,n,1. The serial protocol is very simple, an alternating +send and receive of data packets. Communication is done in 8 byte data packets +and is initiated by the host processor. Once the host processor has sent 8 +bytes, the microcontroller responds with 8 bytes. The packet contains bytes +that can affect the state of the power, led and fan. It also contains bits +reflecting external soft power events. Both packets sent and received follow +the same structure. + +The 8 bytes are decoded as follows: + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Power | LED | LED | Fan | + | State | State | Flash Rate | State | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Fan High Temp | Fan Low Temp | | | + | ON | OFF | ID | CheckSum | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Hex Ascii Comments + --- ----- -------------------------------------------------- +Power State: + 0x62 b Running, nominal running state + 0x63 c Stop, power down immediately (ID == HOST) OR + Stop, the power switch has been activated, stop in 20s + (ID == CONTROLLERxx) OR + Stop, the host has advised Stop + (ID == CONTROLLERxx) + 0x64 d Advise Stop, the host is annoucing its intention + to stop (ID == HOST) + 0x65 e Restart, restart immediately (ID == HOST) OR + Restart, the host has advised Restart + (ID == CONTROLLERxx) + 0x66 f Advise Restart, the host is annoucing its intention + to restart (ID == HOST) + 0x67 g Reset, reset immediately (ID == HOST) OR + Reset, the host has advised Reset + (ID == CONTROLLERxx) + 0x68 h Advise Reset, the host is annoucing its intention + to reset (ID == HOST) + +Except for Running, the Power states are grouped in pairs: Advise [state] and +[state], where state can be: Stop, Restart, or Reset. The Advise state lets +the controller know that there is an intention to either stop, restart or +reset the board. The controller responds by moving to that state and setting +the LED to redflash, but it does not enact the power change. Instead it waits +for the host to issue the actual state before performing the power commands. +For example, assume the microcontroller is reporting the power state to be +[Running, LED Blue]. After the host issues a Advise Stop, the microcontroller +reports [Stop, LED Redflash] and then waits, indefinitely. The Host then +issues a Stop, the microcontroller immediately turns the power off. + +There is nothing in the protocol that requires the Advise [state] packets. The +Host can issue a Stop, Restart, or Reset directly from the Running state and +the microcontroller will immediately enact the change. + +There is nothing in the protocol that forbids moving back to Running from the +Stop, Restart or Reset states, i.e. undoing an Advise [state] packet. + +The exception to that rule is in the Stop state. The Stop state can be reached +by either issuing a Advise Stop or from a softpower switch activation (someone +hits the power switch). If the latter, then a request to move to any other +state is ignored and the power will go off in approximately 20s. + +NOTE 1: There does not appear to be any difference in processing the Restart +and Reset state changes. They both deliver a system restart. + +NOTE 2: Obvious absence of an 'a' state. Both the LED and Fan controls use 'a' +as a state, but Power starts with 'b'. No evidence has shown 'a' to be a +valid state. + +LED State: + 0x61 a Off + 0x62 b Blue + 0x63 c Red + 0x64 d Blue Flash + 0x65 e Red Flash + 0x66 f Alternate1 Blue/Red + 0x67 g Alternate3 3 Blue/3 Red (only on version 5.x boards) + +LED States are self explanatory with one exception. Although state 'g' or +Alternate3 has been observed, it only seems to function on IOMEGA G2 Version +5.x boards and does not respond to rate changes. + +LED Flash Rate: +The flash rate seems to be 1/x seconds on, then 1/x seconds off. So one cycle +of off and on at an LED Flash rate of 1 is almost 2s. The value spans 8 bits +but functionally 0 is off and 36-40 is on. Testing has shown an oddity, the +value 35 is rejected by the microcontroller software and is not set. + +Fan State: + 0x61 a Auto thermostat function + 0x62 b On always on + +Fan High Temp: +High Temp is the temprature in Celsius where the fan is be turned on. + +Fan Low Temp: +Low Temp is the temprature in Celsius where the fan is be turned off. + +ID: +The real purpose of this field is not known. It is known that it is a constant +depending upon the direction of the packets and the board rev. It has been +designated ID as a place holder but it could as easily be defined as version +or it may be something else entirely. + + 0x00 DC2 CONTROLLER00 + IOMEGA G2 Version 5.x Controller ID (recv'd packets) + 0x07 BEL HOST (sent packets) + 0x12 DC2 CONTROLLER12 + IOMEGA G2 Version 3.x Controller ID (recv'd packets) + +Checksum: +The check sum is an 8 bit sum of the first 7 bytes with the most significant +bit cleared. + + Sum = ((b1 + b2 + b3 +b4 +b5 +b6 + b7) & 0x7f) + +The bytes and their meanings were determined by watching the serial port +chatter during specific events such as LED Blue, LED Red, Fan ON, etc. So only +events observed have been decoded. Although all the significant events were +observed and decoded, there are some holes in the understanding of the +protocol. + +There is one special packet that causes the microcontroller to reset. This +packet is: + 0x23696f6d 0x65676115 + (or as a string "#iomega\025") + +The resulting packet from the microcontroller is: + 0x62000000 0x00000062 + +Testing also yielded that a null packet will cause the microcontroller to +feed back the current state. So this packet: + 0x00000000 0x00000000 + +will yield something like this (this is the default state): + 0x62620a61 0x322d1220 + +The default state when the board powers on is: + State: Run + LED: Red + LED Rate: 10 + Fan: On + Fan Temp High: 50C + Fan Temp Low: 45C + +Below is some of the data collected while watching the serial port chatter: + +w: 0x23696f6d 0x65676115 #iomega\025 +r: 0x62000000 0x00000062 b\0\0\0\0\0\0b +w: 0x62630a61 0x322d0716 bc\na2-\7\26 red state +r: 0x62630a61 0x322d1221 bc\na2-\22! +w: 0x62641161 0x322d071e bd\21a2-\7\36 blue flash +r: 0x62641161 0x322d1229 bd\21a2-\22) +w: 0x62641161 0x322d071e bd\21a2-\7\36 blue flash + +LED ok +w: 0x62620a61 0x322d0715 bb\na2-\7\25 +r: 0x62630a61 0x322d1220 bb\na2-\22 + +LED alt +w: 0x626f0a61 0x322d0719 bf\na2-\7\31 +r: 0x626f0a61 0x322d1224 bf\na2-\22$ + +reset +w: 0x68620a61 0x322d071b hb\na2-\7\33 reset +r: 0x67620a61 0x322d0013 gb\na2-\0\23 resetting + +restart +w: 0x66620a61 0x322d0719 fb\na2-\7\31 restart +r: 0x65620a61 0x322d1223 eb\na2-\22# restarting + +shutdown +w: 0x64620a61 0x322d0717 db\na2-\7\27 shutdown +r: 0x63620a61 0x322d1221 cb\na2-\22! power shutting down + +soft Power +r: 0x63620a61 0x322d000f cb\na2-\0\17 power shutting down + + + + + + + + + + + + + |