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Serial interface settings

TBW

Monitoring

There are two kinds of monitoring messages received from the device. There is a "CM2024 SUP" message every second which seems to be an overall status and is used to indicate that a battery is ready to charge (and possibly other things I am yet to figure out). The second type of message is a "CM2024 DAT" which returns the status of each slot independently.

"SUP" Message

First a message like this will arrive

43 4D 32 30 32 34 20 53 55 50                      CM2024 SUP

Followed by another fixed length message like this:

02 00 7B 01 EE 02 0D 00 82 78 78 78 78 78 78 78
78 78 78 78 78 78 78 78 78 78 78 78 78 78 78 78
78 98 16 0D 0A

Then when a battery is inserted it will switch to something like:

01 00 7B 01 ED 02 09 00 13 00 01 01 00 02 00 00
00 3C 05 05 00 08 78 78 78 78 78 78 78 78 78 78
78 73 26 0D 0A

78 is a filler value for no data

So far I have figured out the following:

Offset	Description
01	Unknown
02	Unknown
03	Unknown
04	Unknown
05	Unknown
06	Unknown
07	Unknown
08 - 09	Sequence Counter going from 0x0000 to 0x0257 (0-599) in increments of 13 - Little Endian
10	Slot awaiting setup (see slot table)
11	Chemistry selected (See chemistry table)
12	Program selected (See program table)
13	Selected maximum charge current (applicable for NiHM/Cd only) (see charge current table)
14	Selected discharge rate (see discharge table)
15 - 16	Selected capacity in mAh in units of 1. Little Endian
17	SD card status (see table)
18	Cool time in minutes
19	Unknown
20	Unknown
21	Unknown
22	SD Slot status
23	Unknown
24	Unknown
25	Unknown
26	Unknown
27	Unknown
28	Unknown
29	Unknown
30	Unknown
31	Unknown
32	Unknown
33	Unknown
34 - 35	Unknown - likely a CRC16
36 - 37	Always 0D 0A - \r\n

"DAT" Message

Offset	Description
01 - 02	Sequence Counter going from 0x0000 to 0x0257 (0-599) and resetting - big endian
03	Slot number (see slot table)
04	Chemistry (see chemistry table)
05	Unknown flag - either 0 or 1
06	Program state - always the same as the next value (in 06) unless the program finishes and then it's 0B
07	Program (see program table)
08	Activity Step (see activity table)
09 - 10	Time in minutes - big endian. When Ready, this will stop.
11 - 12	Voltage in units of 0.001 (big endian). e.g. 5F 07 = 1.887
13 - 14	Current in units of 0.001 (big endian). E.g. 17 02 = 0.535
15 - 18	C-CAP stored in units of 0.01 (big endian)
19 - 22	D-CAP stored in units of 0.01 (big endian). e.g. 3D 88 01 00 = 1004.13
23	Unknown
24	Unknown
25	Maximum charge current (see table)
26	Unknown
27	Unknown
28	Pause time in minutes. Windows software allows increments of 30 mins so not sure if other values supported
29 - 30	Battery capacity in mAh - big endian
31	Discharge rate (see discharge rate table)
32	Unknown - Sometimes the same as previous value in 31 so it’s related
33	Unknown
34 - 35	Checksum - CRC-16/MODBUS calculated from bytes 02 to 33
36 - 37	Carriage return - always 0D 0A (i.e. \r\n)

Control

Control messages are send from the PC software to the device. These messages are always 13 bytes long and look like this:

02 00 00 00 00 00 00 00 00 00 01 9D 69

The first byte is always the command type as follows:

Value	Command
01	Start program
02	Cancel
03	Set LCD brightness

Start Program

When the CM2024 SUP message has values in 10 to 18, the charger is indicating that it is ready to receive the start command. In the windows software, this makes the slot blue allowing you to fill out the fields.

Common

This is a set of common enumerated values which appear in various messages.

Slot number

Value	Description
00	Slot 1
01	Slot 2
02	Slot 3
03	Slot 4
04	Slot 5
05	Slot 6
06	Slot 7
07	Slot 8
08	Slot A
09	Slot B

Chemistry Values

Value	Description
01	NiHM/Cd
02	NiZn

Program

Value	Description
00	None / slot empty
01	Recharge
02	Discharge
03	Procharge
04	Cycle
05	Alive
06	Maximize
07	No setup
08	Unknown
09	Unknown
0A	Error
0B	Complete

Activity Step

Value	Description
00	Idle
01	Charging
02	Discharging
03	Ready
04	Unknown
05	Cool Down
06	Error

Charge current

Value	Description
00	Not Applicable (NiZn)
01	500mA
02	1000mA
03	1500mA
04	2000mA
05	2500mA
06	3000mA

Discharge current

The values are interpreted differently depending on the chemistry

NiZn

Value	Description
01	150mA
02	300mA
03	450mA
04	600mA

NiMH/Cd

Value	Description
01	125mA
02	250mA
03	375mA
04	500mA
05	625mA
06	750mA

SD card state

Value	Description
00	SD off
01	Unknown
02	On / Ready

SD slot state

Value	Description
00	NO CARD
01	Unknown
02	Unknown
03	Unknown
04	Unknown
05	Unknown
06	Unknown
07	Inserted
08	Ready