12-bit Grayscale Mode

ISI_DATA[11:0] is the physical interface to the ISI. These bits are sampled and written to memory.

When 12-bit Grayscale mode is enabled, two memory formats are supported:

ISI_CFG2.GS_MODE = 0: two pixels per word

ISI_CFG2.GS_MODE = 1: one pixel per word

The following tables illustrate the memory mapping for the two formats.

Table 1. Grayscale Memory Mapping Configuration for 12-bit Data (ISI_CFG2.GS_MODE = 0: two pixels per word)
31 30 29 28 27 26 25 24
Pixel 0 [11:4]
               
23 22 21 20 19 18 17 16
Pixel 0 [3:0] – – – –
               
15 14 13 12 11 10 9 8
Pixel 1 [11:4]
               
7 6 5 4 3 2 1 0
Pixel 1 [3:0] – – – –

If ISI_CFG1.GRAYLE = 0, the pixels map as follows:

If ISI_CFG1.GRAYLE=1, the pixels map as follows:

Table 2. Grayscale Memory Mapping Configuration for 12-bit Data (ISI_CFG2.GS_MODE = 0: two pixels per word)
31 30 29 28 27 26 25 24
Pixel 1 [11:4]
               
23 22 21 20 19 18 17 16
Pixel 1 [3:0] – – – –
               
15 14 13 12 11 10 9 8
Pixel 0 [11:4]
               
7 6 5 4 3 2 1 0
Pixel 0 [3:0] – – – –
Table 3. Grayscale Memory Mapping Configuration for 12-bit Data (ISI_CFG2.GS_MODE = 1: one pixel per word)
31 30 29 28 27 26 25 24
Pixel 0 [11:4]
               
23 22 21 20 19 18 17 16
Pixel 0 [3:0] – – – –
               
15 14 13 12 11 10 9 8
– – – – – – – –
               
7 6 5 4 3 2 1 0
– – – – – – – –
Parent topic: Memory Interface