Q: Fat16 Format With Micro SD Card

I need to format a micro SD card from my Arduino micro sd reader to fat16.  I followed an online tutorial like so:

diskutil list

Which brought up this list:

/dev/disk0

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *256.1 GB   disk0

   1:                        EFI                         209.7 MB   disk0s1

   2:                  Apple_HFS Macintosh 10.7 SSD      175.0 GB   disk0s2

   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

   4:       Microsoft Basic Data BOOTCAMP                80.2 GB    disk0s4

/dev/disk1

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *750.2 GB   disk1

   1:                        EFI                         209.7 MB   disk1s1

   2:                  Apple_HFS WD 750GB Black HD       749.8 GB   disk1s2

/dev/disk2

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:     FDisk_partition_scheme                        *7.8 GB     disk2

   1:                 DOS_FAT_32 NO NAME                 7.8 GB     disk2s1

Then I typed:

diskutil partitionDisk disk2 MBRFormat "MS-DOS FAT16" NO_NAME 7.8G

Then it displays this:

Started partitioning on disk2

Unmounting disk

Creating the partition map

Waiting for the disks to reappear

Formatting disk2s1 as MS-DOS (FAT16) with name NO_NAME

Error: -69850: The chosen size is not valid for the chosen file system

Although it shows up in Disk Utility as: disk2s1, should I take notice of the Error: -69850 or does it mean I've done it wrong?  Also I've tried different partition sizes and this error still comes up.

P.s. I'm using Mac OS X Lion.

Thanks in advance.