This website is not associated with iRobot. The information presented here applies to Roomba Red Item #4100, Roomba Item #4105, Roomba Discovery Item #4210, and Roomba Discovery SE Item #4220, it does not apply to the original Roomba series.

iRobot New Roomba Hacking

Introduction

This website is dedicated to reverse engineering the new Roomba by iRobot and is not associated with iRobot. The information presented here applies to Roomba Red Item #4100, Roomba Item #4105, Roomba Discovery Item #4210, and Roomba Discovery SE Item #4220, it does not apply to the original Roomba series.

Other Roomba Hacking Links

Disassembly Instruction Original Roomba
Original Roomba with New Brain
Roomba Red Diagnostic Mode

Microcontroller

Motorola MC9S12DG256C CPV – datasheet (pdf 2.7M)
HC12 16 bit microcontroller, equivalent to MC9S19DP256
112 pin LQFP package, 20x20x1.4mm, 0.65mm pin spacing
Clocked with a 6 MHz Xtal
256K flash ROM
12K RAM
4K EEPROM
2x UART (pin89 RXD0, pin90 TXD0, pin91 RXD1, pin92 TXD1)
2x SPI
8x timer
2x 16 channel 10bit ADC
8x PWM
89x I/O channels
2x CAN 2.0A/B
1x I2C

The Roomba uses a tick timer with 4096 ticks per minute, this corresponds to the 67 times per second that the robot evaluates its state mentioned on the box.

Microcontroller Functional Pinout

Pin	Name	I/O	Cat.	Description
3	PWM1	O	nav	Motor R Control1. H=on
4	PWM0	O	nav	Motor R Control2. H=on
9	IOC0	I	nav	Motor R Encoder
10	IOC1	I	nav	Motor L Encoder
12	IOC3	I	vac	Side Brush Overcurrent = H
15	IOC4	I	nav	Motor R Overcurrent Sensor. H=overcurrent
16	IOC5	I	nav	Motor L Overcurrent Sensor. H=overcurrent
17	IOC6	I	vac	Main Brush Overcurrent = H
23	PB0	I	vac	Side Brush Motor Control. H=on
25	PB1	I	vac	Vac Motor Control. H=on
26	PB2	I	vac	Main Brush Motor Control. H=on
27	PB3	I	pow	Aux Power Control. H=on
28	PB4	O???	pow	??? Charger Enable
29	PB5	O	pow	Charger Control. H=enable charging
30	PB6	O	nav	Floor and Side Sensors Control. H=on
32	KWH7	I	ui	Input Pin on Serial Connector
33	KWH6	I	nav	Wheel-Up Switches. H=ok
34	KWH5	I	ui	Spot Button. L=pressed
35	KWH4	I	ui	Unconnected Button. L=pressed
49	KWH3	I	ui	Clean Button. L=pressed
50	KWH2	I	pow	Any Charger Connected (AC or Floor). H=yes
51	KWH1	I	ui	IR-Receiver
52	KWH0	I	ui	Power Button. L=pressed
57	PA0	I	vac	Dust Sensor1
58	PA1	I	vac	Dust Sensor2
59	PA2	I	nav	Bump Sensor L
60	PA3	I	nav	Bump Sensor R
62	PA5	I	pow	AC Charger Connected. H=yes
63	PA6	O	sys	Reset Watchdog Timer (1.6 sec timeout)
64	PA7	O	pow	??? Charger Safety Board. H=charger ok
67	AN00	I	pow	Bat Voltage. V(mV) = ADC * 28.1
68	AN08	I	vac	Vac Motor Current. I(mA) = ADC * 5
69	AN01	I	pow	Bat Temperature. T(degC) = 25 + (512 - ADC) / 9
70	AN09	O	pow	??? Bat Temperature Sense Enable. H=Enable
71	AN02	I	pow	Bat Current. I(mA) = (ADC - 512) * 6.523. Positive = charging, negative=discharging
73	AN03	I	nav	Floor Sensor L Back
75	AN04	I	nav	Floor Sensor L Front 
77	AN05	I	nav	Floor Sensor R Back 
79	AN06	I	nav	Floor Sensor R Front 
81	AN07	I	nav	Side Wall Sensor
87	PM7	O	ui	Power Led Green. H=on
88	PM6	O	ui	Power Led Red. H=on
91	RXD1	I	ui	Serial Port
92	TXD1	O	ui	Serial Port
100	PM5	O	ui	Status Led Green. H=on
101	PM4	O	ui	Status Led Red. H=on
102	PM3	O	ui	Dust-Detect Led Blue. H=on
103	PM2	O	ui	Spot Led Green. H=on
104	PM1	O	ui	Unconnected Led. H=on
105	PM0	O	ui	Clean Led Green. H=on
111	PWM5	O	nav	Motor L Control1. H=on
112	PWM4	O	nav	Motor L Control2. H=on

PCB Frontside

(click to enlarge)

Connectors Top Left to Right

J1 purple/purple – speaker, gray/white – left motor down switch
J3 – main brush motor
J4 – left motor and encoder (32 pins per revolution)
J9 – dirt sensors
J10 – to top panel, right side IR wall sensor
J16 – right motor and encoder
J17 black/red – vacuum motor in dust container
J18 black/green – side brush motor
J19 black/yellow – right motor down switch
J15 black/red – battery charger connector

Connector Bottom

J11 7 pin serial port connector 57600 baud 8-N-1

PCB Backside

(click to enlarge)

Connectors Left Top

J7 red/white/black – battery
J25 – bottom battery recharge pads
J2 – stairs sensors

Connectors Left Bottom

J22 green/green = front wheel down switch, purple/purple – front wheel down sensor
J8 – front bumper board

Connector Right Top

J24 – stair sensors

Connector Right Bottom

J23 red/blue/black – front bumper board, IR receiver: red – vcc, blue – IR signal, black – grd

Hidden under plastic cover above the charger plug is a serial port connector. iRobot does not provide support for the serial port, the following quote is from the FAQ section on the iRobot.com website:

Does iRobot provide any codes or specifications for the port?
No, iRobot does not provide this information.
Attempting to alter Roomba’s programming voids the warranty.

Serial Port Specification

The serial port runs at 57600 baud 8N1 with 5 Volt levels. To connect the Roomba port to a PC you have to use a level converter, to convert the 0 and 5 Volt levels of the Roomba port to the approximate -10 and 10 volt levels of the PC port. For level converters see: Simple RS232C Level Converter using Transistors or MAX232 ic.

Serial Connector Pinout

   ___
  |6 7|
 /4   5\
 \1 2 3/
  -- --  

pin1 black – microcontroller pin32 (PH7) via 1K resistor R236, internally pulled up to +5V
pin2 brown – GRD
pin3 red – GRD
pin4 orange – microcontroller pin91 (RXD1) via 1K resistor R239
pin5 yellow – microcontroller pin92 (TXD1) via 1K resistor R238 and 100ohm resistor R243
pin6 blue – battery (+15.6volt)
pin7 white – battery (+15.6volt)

Results

Power Connect

Inserting battery pack displays: ( [^C] is control-C character hex 03 )

bl-start[^C]2004-05-26-1037-L   [^C]Roomba by iRobot!
MC9S12DP256
2004-07-30-1026-L
battery-current-quiescent-raw 525  battery-current-zero 511
 
2004-07-30-1026-L
 
processor-sleep

Hex dump of reply:

0000:62 6C 2D 73 74 61 72 74 bl-start
0008:03 32 30 30 34 2D 30 35  2004-05
0010:2D 32 36 2D 31 30 33 37 -26-1037
0018:2D 4C 20 20 20 03 52 6F -L    Ro
0020:6F 6D 62 61 20 62 79 20 omba by 
0028:69 52 6F 62 6F 74 21 0D iRobot! 
0030:0A 4D 43 39 53 31 32 44  MC9S12D
0038:50 32 35 36 0D 0A 32 30 P256  20
0040:30 34 2D 30 37 2D 33 30 04-07-30
0048:2D 31 30 32 36 2D 4C 20 -1026-L 
0050:20 20 0D 0A 62 61 74 74     batt
0058:65 72 79 2D 63 75 72 72 ery-curr
0060:65 6E 74 2D 71 75 69 65 ent-quie
0068:73 63 65 6E 74 2D 72 61 scent-ra
0070:77 20 35 32 35 20 20 62 w 525  b
0078:61 74 74 65 72 79 2D 63 attery-c
0080:75 72 72 65 6E 74 2D 7A urrent-z
0088:65 72 6F 20 35 31 31 0D ero 511 
0090:0A 0D 0A 32 30 30 34 2D    2004-
0098:30 37 2D 33 30 2D 31 30 07-30-10
00A0:32 36 2D 4C 20 20 20 0D 26-L    
00A8:0A 0D 0A 70 72 6F 63 65    proce
00B0:73 73 6F 72 2D 73 6C 65 ssor-sle
00B8:65 70 0D 0A             ep 

Power On

Switching power on (turning on green battery led) displays:

key-wakeup
slept for 764 minutes 1091 ticks
 
2004-07-30-1026-L
battery-current-quiescent-raw 525  battery-current-zero 511

Power Off

Switching power off (turning off green battery led) displays:

processor-sleep

Button Press

Pressing a button on top of the Roomba while power is off displays: (nothing is displayed if power is on)

key-wakeup
slept for 765 minutes 3995 ticks
 
2004-07-30-1026-L
 
processor-sleep

Serial Port Pin Input

Grounding pin1 while power is off displays:

key-wakeup
slept for 763 minutes 1841 ticks
 
2004-07-30-1026-L
device-detect
2004-07-30-1026-L
 
processor-sleep

Grounding pin1 while power is on displays:

device-detect
2004-07-30-1026-L

Reset via Serial Port

While on, sending control-G resets the roomba as if the battery pack was just inserted:

bl-start[^C]2004-05-26-1037-L   [^C]Roomba by iRobot!
MC9S12DP256
2004-07-30-1026-L
battery-current-quiescent-raw 525  battery-current-zero 511
 
2004-07-30-1026-L
 
processor-sleep

Charging the Battery

While the battery is being charged the serial port reports every second the charge time, battery voltage, current and temperature. Below is the part of the serial output where the charger is shut off because of reaching the battery temperature limit.

bat:   min 240  sec 57  mV 16921  mA 572  deg-C 60  
bat:   min 240  sec 58  mV 16921  mA 579  deg-C 60  
bat:   min 240  sec 59  mV 16921  mA 572  deg-C 60  
charging-done: temperature max allowed @ minutes 241
do-charging-wait-for-trickle @ minutes 241
bat:   min 241  sec 0  mV 16866  mA 26  deg-C 60  
bat:   min 241  sec 1  mV 16810  mA -27  deg-C 60  
bat:   min 241  sec 2  mV 16782  mA -27  deg-C 60  

Factory Self Test

Hold down Spot and Clean, then press Power briefly and the LED lights will begin to flash. You can now cycle between the diagnostic modes by using Clean to advance in the sequence, and Spot to return to the diagnostic mode before. For more details see: Roomba Red Diagnostic Mode. Below is the output on the serial port during self test/diagnostics:

factory-test 0  leds
wait: false
 
 
factory-test 1  bumpers
(bump-left?) PASS
(bump-right?) PASS
 
 
factory-test 2  cliffs-side
wiff: cliff-left on 3627  off 3640  signal 13  on? 0
wiff: cliff-front-left on 3628  off 3633  signal 5  on? 1
wiff: cliff-front-right on 3644  off 3644  signal 0  on? 1
wiff: cliff-right on 3644  off 3644  signal 0  on? 1
wiff: wall on 3652  off 3652  signal 0  on? 0
(cliff-left?) PASS
(cliff-right?) FAIL
 
 
factory-test 3  cliffs-front
(cliff-front-left?) FAIL
 
 
factory-test 4  wheel-drop-and-wall
(wheel-drop?) FAIL
 
 
factory-test 5  rcon-receiver
(rcon?)
 
factory-test 6  battery-sensors
(battery-voltage-ok?) PASS
(battery-temperature-ok?) PASS
(baseline-current-ok?) mA -92  min -202  max -14  mV 16309  degrees-C 58 PASS
 
 
factory-test 7  left-wheel
not left-wheel-stall PASS
(baseline-current-ok?) mA -92  min -202  max -14  mV 16309  degrees-C 58 PASS
(drive-speed-ok? left forward) PASS
(drive-speed-ok? right stopped) PASS
(left-drive-current-ok?) mA -183  min -326  max -118  mV 16253  degrees-C 58 PASS
not left-wheel-stall PASS
wait: left-wheel-stall
 
 
factory-test 8  right-wheel
not right-wheel-stall PASS
(baseline-current-ok?) mA -92  min -202  max -14  mV 16281  degrees-C 58 PASS
(drive-speed-ok? left stopped) PASS
(drive-speed-ok? right forward) PASS
(right-drive-current-ok?) mA -183  min -326  max -118  mV 16226  degrees-C 58 PASS
not right-wheel-stall PASS
wait: right-wheel-stall
 
 
factory-test 9  wheel-encoders
(drive-speed-ok? left stopped) PASS
(drive-speed-ok? right stopped) PASS
(drive-speed-ok? left reverse) PASS
(drive-speed-ok? right reverse) PASS
 
 
factory-test 10  stasis
wait: (not (stasis?))
 
 
factory-test 11  main-brush
not brush-motor-stall PASS
(baseline-current-ok?) mA -92  min -202  max -14  mV 16281  degrees-C 58 PASS
(brush-current-ok?) mA -287  min -599  max -241  mV 16226  degrees-C 58 PASS
not brush-motor-stall PASS
wait: brush-motor-stall
 
 
factory-test 12  debris
(debris-left?)
 
factory-test 13  vacuum
not vacuum-motor-stall PASS
(baseline-current-ok?) mA -92  min -202  max -14  mV 16281  degrees-C 58 PASS
not vacuum-motor-stall PASS
(vacuum-current-ok?) mA -7  min -352  max -176  mV 16281  degrees-C 58 FAIL
 
 
factory-test 14  side-brush
not side-brush-motor-stall PASS
(baseline-current-ok?) mA -92  min -202  max -14  mV 16281  degrees-C 57 PASS
not side-brush-motor-stall PASS
(side-brush-current-ok?) mA -7  min -248  max -53  mV 16281  degrees-C 57 FAIL
 
 
factory-test 15  int-charger-prep
not (int-charger-available?) PASS
wait: (int-charger-available?)
 
 
factory-test 16  int-charger-on
wait: (int-charger-available?)
 
 
factory-test 17  int-charger-trickle
wait: (int-charger-available?)
 
 
factory-test 18  ext-charger-prep
not (ext-charger-available?) PASS
wait: (ext-charger-available?)
 
 
factory-test 19  ext-charger-on
wait: (ext-charger-available?)
 
 
factory-test 20  ext-charger-trickle
wait: (ext-charger-available?)
 
 
factory-test 21  bootloader
(bootloader-ok?) PASS
 
 
factory-test 22  complete
 
 
 
SUMMARY: START
SUMMARY: DATE-TAG 2004-07-30-1026-L   
SUMMARY: (baseline-current-ok?) PASS   mA -92  min -202  max -14  mV 16281  degrees-C 57
SUMMARY: (left-drive-current-ok?) PASS   mA -183  min -326  max -118  mV 16253  degrees-C 58
SUMMARY: (left-drive-stall-current-ok?) untested   
SUMMARY: (right-drive-current-ok?) PASS   mA -183  min -326  max -118  mV 16226  degrees-C 58
SUMMARY: (right-drive-stall-current-ok?) untested   
SUMMARY: (brush-current-ok?) PASS   mA -287  min -599  max -241  mV 16226  degrees-C 58
SUMMARY: (brush-stall-current-ok?) untested   
SUMMARY: (side-brush-current-ok?) FAIL   mA -7  min -248  max -53  mV 16281  degrees-C 57
SUMMARY: (side-brush-stall-current-ok?) untested   
SUMMARY: (vacuum-current-ok?) FAIL   mA -7  min -352  max -176  mV 16281  degrees-C 58
SUMMARY: (vacuum-stall-current-ok?) untested   
SUMMARY: (int-charging-current-ok?) untested   
SUMMARY: (int-charging-trickle-current-ok?) untested   
SUMMARY: (ext-charging-current-ok?) untested   
SUMMARY: (ext-charging-trickle-current-ok?) untested   
SUMMARY: (bump-left?) PASS   
SUMMARY: (bump-right?) PASS   
SUMMARY: (cliff-left?) PASS   
SUMMARY: (cliff-right?) FAIL   
SUMMARY: (cliff-front-left?) FAIL   
SUMMARY: (cliff-front-right?) untested   
SUMMARY: (wheel-drop?) FAIL   
SUMMARY: (wall?) untested   
SUMMARY: (rcon?) FAIL   
SUMMARY: (any-remote-opcode?) untested   
SUMMARY: (battery-voltage-ok?) PASS   
SUMMARY: (battery-temperature-ok?) PASS   
SUMMARY: left-wheel-stall PASS   
SUMMARY: (drive-speed-ok? left forward) PASS   
SUMMARY: (drive-speed-ok? right stopped) PASS   
SUMMARY: right-wheel-stall PASS   
SUMMARY: (drive-speed-ok? right forward) PASS   
SUMMARY: (drive-speed-ok? left stopped) PASS   
SUMMARY: (drive-speed-ok? left reverse) PASS   
SUMMARY: (drive-speed-ok? right reverse) PASS   
SUMMARY: (stasis?) untested   
SUMMARY: brush-motor-stall PASS   
SUMMARY: (debris-left?) FAIL   
SUMMARY: (debris-right?) untested   
SUMMARY: vacuum-motor-stall PASS   
SUMMARY: side-brush-motor-stall PASS   
SUMMARY: (int-charger-available?) PASS   
SUMMARY: (ext-charger-available?) PASS   
SUMMARY: (bootloader-ok?) PASS   
SUMMARY: END