ARM AMBA NIC-301 Especificações descarregar pdf (Página 38)

Hardware Description

ID062813 Non-Confidential

2.6.2 Energy meter

The Daughterboard Configuration Controller firmware supports an on-board energy meter that

enables you to measure the energy consumption of core supplies. The energy meter runs as a

background task on the Daughterboard Configuration Controller and does not load the main

core software except when you request a reading through the SYS_CFG interface.

You can use the energy meter to determine the amount of energy that a specific software

function consumes. You read the energy before and after the function operates, and the

difference between the two represents the amount of energy that the function consumes.

The energy meter accumulates core power supply at a rate of 10000 samples per second. You

can read accumulated energy since reset in Micro-Joules through the SYS_CFGCTRL register

interface.

A 64-bit value represents the total energy. This requires two 32-bit reads from the SYS_CFG

interface. You must read the lower 32 bits followed by the upper 32 bits. When you read the

lower 32 bits, the 64-bit data transfers to two temporary storage registers in the Daughterboard

Configuration Controller and you then receive the lower 32 bits from the lower storage register.

You then read the upper 32 bits and receive the value from the upper storage register.

If you read the upper 32 bits first, no data transfers to the storage register and you receive a false

energy reading.

The energy value is the energy since reset. You can also clear the energy value by writing

0x0000_0000

to the lower 32 bits.

Table 2-7 shows the device numbers for monitoring the cluster energy consumption.

See the Motherboard Express µATX Technical Reference Manual for more information on the

SYS_CFGCTRL registers.

Table 2-7 Cluster energy monitors

Device Cluster energy Description

0 Jcore Energy meter for the two A15 cores, lower 32 bits, total energy

1 Jcore Energy meter for the two A15 cores, upper 32 bits, total energy

2 Jcore Energy meter for the three A7 cores, lower 32 bits, total energy

3 Jcore Energy meter for the three A7 cores, upper 32 bits, total energy

1 2 ... 33 34 35 36 37 38 39 40 41 42 43 ... 177 178

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